2011-03-07 00:39:14 +01:00
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/*-------------------------------------------------------------------------
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*
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* syncrep.c
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*
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* Synchronous replication is new as of PostgreSQL 9.1.
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*
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Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
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* If requested, transaction commits wait until their commit LSN are
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* acknowledged by the synchronous standbys.
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2011-03-07 00:39:14 +01:00
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*
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* This module contains the code for waiting and release of backends.
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* All code in this module executes on the primary. The core streaming
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* replication transport remains within WALreceiver/WALsender modules.
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*
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* The essence of this design is that it isolates all logic about
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* waiting/releasing onto the primary. The primary defines which standbys
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Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
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* it wishes to wait for. The standbys are completely unaware of the
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2011-03-07 00:39:14 +01:00
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* durability requirements of transactions on the primary, reducing the
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* complexity of the code and streamlining both standby operations and
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* network bandwidth because there is no requirement to ship
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* per-transaction state information.
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*
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* Replication is either synchronous or not synchronous (async). If it is
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2012-01-24 21:22:37 +01:00
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* async, we just fastpath out of here. If it is sync, then we wait for
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Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
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* the write, flush or apply location on the standby before releasing
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* the waiting backend. Further complexity in that interaction is
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* expected in later releases.
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2011-03-07 00:39:14 +01:00
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*
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* The best performing way to manage the waiting backends is to have a
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* single ordered queue of waiting backends, so that we can avoid
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* searching the through all waiters each time we receive a reply.
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*
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Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
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* In 9.5 or before only a single standby could be considered as
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2016-12-19 13:15:30 +01:00
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* synchronous. In 9.6 we support a priority-based multiple synchronous
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* standbys. In 10.0 a quorum-based multiple synchronous standbys is also
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* supported. The number of synchronous standbys that transactions
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* must wait for replies from is specified in synchronous_standby_names.
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* This parameter also specifies a list of standby names and the method
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* (FIRST and ANY) to choose synchronous standbys from the listed ones.
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*
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* The method FIRST specifies a priority-based synchronous replication
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* and makes transaction commits wait until their WAL records are
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* replicated to the requested number of synchronous standbys chosen based
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* on their priorities. The standbys whose names appear earlier in the list
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* are given higher priority and will be considered as synchronous.
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* Other standby servers appearing later in this list represent potential
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* synchronous standbys. If any of the current synchronous standbys
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* disconnects for whatever reason, it will be replaced immediately with
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* the next-highest-priority standby.
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*
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* The method ANY specifies a quorum-based synchronous replication
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* and makes transaction commits wait until their WAL records are
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* replicated to at least the requested number of synchronous standbys
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* in the list. All the standbys appearing in the list are considered as
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* candidates for quorum synchronous standbys.
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Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
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*
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2017-04-18 19:58:28 +02:00
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* If neither FIRST nor ANY is specified, FIRST is used as the method.
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* This is for backward compatibility with 9.6 or before where only a
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* priority-based sync replication was supported.
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*
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Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
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* Before the standbys chosen from synchronous_standby_names can
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* become the synchronous standbys they must have caught up with
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* the primary; that may take some time. Once caught up,
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2016-12-19 13:15:30 +01:00
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* the standbys which are considered as synchronous at that moment
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* will release waiters from the queue.
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2011-03-07 00:39:14 +01:00
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*
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2017-01-03 19:48:53 +01:00
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* Portions Copyright (c) 2010-2017, PostgreSQL Global Development Group
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2011-03-07 00:39:14 +01:00
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*
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* IDENTIFICATION
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2011-03-10 07:05:33 +01:00
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* src/backend/replication/syncrep.c
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2011-03-07 00:39:14 +01:00
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <unistd.h>
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#include "access/xact.h"
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#include "miscadmin.h"
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2016-10-04 16:50:13 +02:00
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#include "pgstat.h"
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2011-09-04 07:13:16 +02:00
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#include "replication/syncrep.h"
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#include "replication/walsender.h"
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2011-09-12 20:24:29 +02:00
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#include "replication/walsender_private.h"
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2011-03-07 00:39:14 +01:00
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#include "storage/pmsignal.h"
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2011-09-04 07:13:16 +02:00
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#include "storage/proc.h"
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Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
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#include "tcop/tcopprot.h"
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2011-03-07 00:39:14 +01:00
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#include "utils/builtins.h"
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#include "utils/ps_status.h"
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/* User-settable parameters for sync rep */
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2011-04-10 17:42:00 +02:00
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char *SyncRepStandbyNames;
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2011-03-07 00:39:14 +01:00
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Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
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#define SyncStandbysDefined() \
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(SyncRepStandbyNames != NULL && SyncRepStandbyNames[0] != '\0')
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2011-03-07 00:39:14 +01:00
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static bool announce_next_takeover = true;
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2016-12-19 13:15:30 +01:00
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SyncRepConfigData *SyncRepConfig = NULL;
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2012-01-24 21:22:37 +01:00
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static int SyncRepWaitMode = SYNC_REP_NO_WAIT;
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static void SyncRepQueueInsert(int mode);
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Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
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static void SyncRepCancelWait(void);
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2015-03-26 02:34:08 +01:00
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static int SyncRepWakeQueue(bool all, int mode);
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2011-03-07 00:39:14 +01:00
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2016-12-19 13:15:30 +01:00
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static bool SyncRepGetSyncRecPtr(XLogRecPtr *writePtr,
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2017-05-17 22:31:56 +02:00
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XLogRecPtr *flushPtr,
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XLogRecPtr *applyPtr,
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bool *am_sync);
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2016-12-19 13:15:30 +01:00
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static void SyncRepGetOldestSyncRecPtr(XLogRecPtr *writePtr,
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2017-05-17 22:31:56 +02:00
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XLogRecPtr *flushPtr,
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XLogRecPtr *applyPtr,
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List *sync_standbys);
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2016-12-19 13:15:30 +01:00
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static void SyncRepGetNthLatestSyncRecPtr(XLogRecPtr *writePtr,
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2017-05-17 22:31:56 +02:00
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XLogRecPtr *flushPtr,
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XLogRecPtr *applyPtr,
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List *sync_standbys, uint8 nth);
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2011-04-10 17:42:00 +02:00
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static int SyncRepGetStandbyPriority(void);
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2016-12-19 13:15:30 +01:00
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static List *SyncRepGetSyncStandbysPriority(bool *am_sync);
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static List *SyncRepGetSyncStandbysQuorum(bool *am_sync);
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static int cmp_lsn(const void *a, const void *b);
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2011-04-10 17:42:00 +02:00
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2011-03-07 08:56:53 +01:00
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#ifdef USE_ASSERT_CHECKING
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2012-01-24 21:22:37 +01:00
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static bool SyncRepQueueIsOrderedByLSN(int mode);
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2011-03-07 08:56:53 +01:00
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#endif
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2011-03-07 00:39:14 +01:00
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/*
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* ===========================================================
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* Synchronous Replication functions for normal user backends
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* ===========================================================
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*/
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/*
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* Wait for synchronous replication, if requested by user.
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Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
*
|
|
|
|
* Initially backends start in state SYNC_REP_NOT_WAITING and then
|
|
|
|
* change that state to SYNC_REP_WAITING before adding ourselves
|
|
|
|
* to the wait queue. During SyncRepWakeQueue() a WALSender changes
|
|
|
|
* the state to SYNC_REP_WAIT_COMPLETE once replication is confirmed.
|
|
|
|
* This backend then resets its state to SYNC_REP_NOT_WAITING.
|
2016-03-30 03:16:12 +02:00
|
|
|
*
|
|
|
|
* 'lsn' represents the LSN to wait for. 'commit' indicates whether this LSN
|
|
|
|
* represents a commit record. If it doesn't, then we wait only for the WAL
|
|
|
|
* to be flushed if synchronous_commit is set to the higher level of
|
|
|
|
* remote_apply, because only commit records provide apply feedback.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
|
|
|
void
|
2016-03-30 03:16:12 +02:00
|
|
|
SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
2011-04-10 17:42:00 +02:00
|
|
|
char *new_status = NULL;
|
2011-03-07 00:39:14 +01:00
|
|
|
const char *old_status;
|
2016-03-30 03:16:12 +02:00
|
|
|
int mode;
|
|
|
|
|
|
|
|
/* Cap the level for anything other than commit to remote flush only. */
|
|
|
|
if (commit)
|
|
|
|
mode = SyncRepWaitMode;
|
|
|
|
else
|
|
|
|
mode = Min(SyncRepWaitMode, SYNC_REP_WAIT_FLUSH);
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
2017-12-29 15:30:33 +01:00
|
|
|
* Fast exit if user has not requested sync replication.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2017-12-29 15:30:33 +01:00
|
|
|
if (!SyncRepRequested())
|
2011-03-07 00:39:14 +01:00
|
|
|
return;
|
|
|
|
|
|
|
|
Assert(SHMQueueIsDetached(&(MyProc->syncRepLinks)));
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
Assert(WalSndCtl != NULL);
|
|
|
|
|
|
|
|
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
|
|
|
|
Assert(MyProc->syncRepState == SYNC_REP_NOT_WAITING);
|
2011-03-26 11:09:37 +01:00
|
|
|
|
|
|
|
/*
|
2011-04-10 17:42:00 +02:00
|
|
|
* We don't wait for sync rep if WalSndCtl->sync_standbys_defined is not
|
|
|
|
* set. See SyncRepUpdateSyncStandbysDefined.
|
2011-03-26 11:09:37 +01:00
|
|
|
*
|
2011-04-10 17:42:00 +02:00
|
|
|
* Also check that the standby hasn't already replied. Unlikely race
|
2014-05-06 18:12:18 +02:00
|
|
|
* condition but we'll be fetching that cache line anyway so it's likely
|
|
|
|
* to be a low cost check.
|
2011-03-26 11:09:37 +01:00
|
|
|
*/
|
|
|
|
if (!WalSndCtl->sync_standbys_defined ||
|
2016-03-30 03:16:12 +02:00
|
|
|
lsn <= WalSndCtl->lsn[mode])
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
{
|
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
return;
|
|
|
|
}
|
2011-03-26 11:09:37 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Set our waitLSN so WALSender will know when to wake us, and add
|
|
|
|
* ourselves to the queue.
|
|
|
|
*/
|
2016-03-30 03:16:12 +02:00
|
|
|
MyProc->waitLSN = lsn;
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
MyProc->syncRepState = SYNC_REP_WAITING;
|
2012-01-30 15:36:17 +01:00
|
|
|
SyncRepQueueInsert(mode);
|
|
|
|
Assert(SyncRepQueueIsOrderedByLSN(mode));
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
|
|
|
|
/* Alter ps display to show waiting for sync rep. */
|
|
|
|
if (update_process_title)
|
|
|
|
{
|
|
|
|
int len;
|
|
|
|
|
|
|
|
old_status = get_ps_display(&len);
|
|
|
|
new_status = (char *) palloc(len + 32 + 1);
|
|
|
|
memcpy(new_status, old_status, len);
|
|
|
|
sprintf(new_status + len, " waiting for %X/%X",
|
2016-03-30 03:16:12 +02:00
|
|
|
(uint32) (lsn >> 32), (uint32) lsn);
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
set_ps_display(new_status, false);
|
|
|
|
new_status[len] = '\0'; /* truncate off " waiting ..." */
|
|
|
|
}
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Wait for specified LSN to be confirmed.
|
|
|
|
*
|
|
|
|
* Each proc has its own wait latch, so we perform a normal latch
|
|
|
|
* check/wait loop here.
|
|
|
|
*/
|
|
|
|
for (;;)
|
|
|
|
{
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
/* Must reset the latch before testing state. */
|
2015-01-14 18:45:22 +01:00
|
|
|
ResetLatch(MyLatch);
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
2016-08-15 19:42:51 +02:00
|
|
|
* Acquiring the lock is not needed, the latch ensures proper
|
|
|
|
* barriers. If it looks like we're done, we must really be done,
|
|
|
|
* because once walsender changes the state to SYNC_REP_WAIT_COMPLETE,
|
|
|
|
* it will never update it again, so we can't be seeing a stale value
|
|
|
|
* in that case.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2016-08-12 13:43:45 +02:00
|
|
|
if (MyProc->syncRepState == SYNC_REP_WAIT_COMPLETE)
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
break;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
* If a wait for synchronous replication is pending, we can neither
|
2011-04-10 17:42:00 +02:00
|
|
|
* acknowledge the commit nor raise ERROR or FATAL. The latter would
|
2016-06-10 00:02:36 +02:00
|
|
|
* lead the client to believe that the transaction aborted, which is
|
|
|
|
* not true: it's already committed locally. The former is no good
|
2011-04-10 17:42:00 +02:00
|
|
|
* either: the client has requested synchronous replication, and is
|
|
|
|
* entitled to assume that an acknowledged commit is also replicated,
|
2011-06-21 23:33:20 +02:00
|
|
|
* which might not be true. So in this case we issue a WARNING (which
|
2011-04-10 17:42:00 +02:00
|
|
|
* some clients may be able to interpret) and shut off further output.
|
|
|
|
* We do NOT reset ProcDiePending, so that the process will die after
|
|
|
|
* the commit is cleaned up.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
if (ProcDiePending)
|
|
|
|
{
|
|
|
|
ereport(WARNING,
|
|
|
|
(errcode(ERRCODE_ADMIN_SHUTDOWN),
|
2011-03-18 15:20:22 +01:00
|
|
|
errmsg("canceling the wait for synchronous replication and terminating connection due to administrator command"),
|
2011-06-21 23:33:20 +02:00
|
|
|
errdetail("The transaction has already committed locally, but might not have been replicated to the standby.")));
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
whereToSendOutput = DestNone;
|
|
|
|
SyncRepCancelWait();
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* It's unclear what to do if a query cancel interrupt arrives. We
|
|
|
|
* can't actually abort at this point, but ignoring the interrupt
|
2011-04-10 17:42:00 +02:00
|
|
|
* altogether is not helpful, so we just terminate the wait with a
|
|
|
|
* suitable warning.
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
*/
|
|
|
|
if (QueryCancelPending)
|
|
|
|
{
|
|
|
|
QueryCancelPending = false;
|
|
|
|
ereport(WARNING,
|
|
|
|
(errmsg("canceling wait for synchronous replication due to user request"),
|
2011-06-21 23:33:20 +02:00
|
|
|
errdetail("The transaction has already committed locally, but might not have been replicated to the standby.")));
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
SyncRepCancelWait();
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2011-04-10 17:42:00 +02:00
|
|
|
* If the postmaster dies, we'll probably never get an
|
2011-06-09 20:32:50 +02:00
|
|
|
* acknowledgement, because all the wal sender processes will exit. So
|
|
|
|
* just bail out.
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
*/
|
Introduce a pipe between postmaster and each backend, which can be used to
detect postmaster death. Postmaster keeps the write-end of the pipe open,
so when it dies, children get EOF in the read-end. That can conveniently
be waited for in select(), which allows eliminating some of the polling
loops that check for postmaster death. This patch doesn't yet change all
the loops to use the new mechanism, expect a follow-on patch to do that.
This changes the interface to WaitLatch, so that it takes as argument a
bitmask of events that it waits for. Possible events are latch set, timeout,
postmaster death, and socket becoming readable or writeable.
The pipe method behaves slightly differently from the kill() method
previously used in PostmasterIsAlive() in the case that postmaster has died,
but its parent has not yet read its exit code with waitpid(). The pipe
returns EOF as soon as the process dies, but kill() continues to return
true until waitpid() has been called (IOW while the process is a zombie).
Because of that, change PostmasterIsAlive() to use the pipe too, otherwise
WaitLatch() would return immediately with WL_POSTMASTER_DEATH, while
PostmasterIsAlive() would claim it's still alive. That could easily lead to
busy-waiting while postmaster is in zombie state.
Peter Geoghegan with further changes by me, reviewed by Fujii Masao and
Florian Pflug.
2011-07-08 17:27:49 +02:00
|
|
|
if (!PostmasterIsAlive())
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
{
|
|
|
|
ProcDiePending = true;
|
|
|
|
whereToSendOutput = DestNone;
|
|
|
|
SyncRepCancelWait();
|
|
|
|
break;
|
|
|
|
}
|
2011-08-09 21:30:45 +02:00
|
|
|
|
|
|
|
/*
|
2012-06-10 21:20:04 +02:00
|
|
|
* Wait on latch. Any condition that should wake us up will set the
|
|
|
|
* latch, so no need for timeout.
|
2011-08-09 21:30:45 +02:00
|
|
|
*/
|
2016-10-04 16:50:13 +02:00
|
|
|
WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
|
|
|
|
WAIT_EVENT_SYNC_REP);
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* WalSender has checked our LSN and has removed us from queue. Clean up
|
|
|
|
* state and leave. It's OK to reset these shared memory fields without
|
|
|
|
* holding SyncRepLock, because any walsenders will ignore us anyway when
|
2017-08-14 23:29:33 +02:00
|
|
|
* we're not on the queue. We need a read barrier to make sure we see the
|
|
|
|
* changes to the queue link (this might be unnecessary without
|
2017-07-12 14:30:52 +02:00
|
|
|
* assertions, but better safe than sorry).
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
*/
|
2017-07-12 14:30:52 +02:00
|
|
|
pg_read_barrier();
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
Assert(SHMQueueIsDetached(&(MyProc->syncRepLinks)));
|
|
|
|
MyProc->syncRepState = SYNC_REP_NOT_WAITING;
|
2012-06-24 17:51:37 +02:00
|
|
|
MyProc->waitLSN = 0;
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
|
|
|
|
if (new_status)
|
|
|
|
{
|
|
|
|
/* Reset ps display */
|
|
|
|
set_ps_display(new_status, false);
|
|
|
|
pfree(new_status);
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2012-01-24 21:22:37 +01:00
|
|
|
* Insert MyProc into the specified SyncRepQueue, maintaining sorted invariant.
|
2011-03-07 00:39:14 +01:00
|
|
|
*
|
2011-03-10 21:56:18 +01:00
|
|
|
* Usually we will go at tail of queue, though it's possible that we arrive
|
2011-03-07 00:39:14 +01:00
|
|
|
* here out of order, so start at tail and work back to insertion point.
|
|
|
|
*/
|
|
|
|
static void
|
2012-01-24 21:22:37 +01:00
|
|
|
SyncRepQueueInsert(int mode)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
2011-04-10 17:42:00 +02:00
|
|
|
PGPROC *proc;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);
|
|
|
|
proc = (PGPROC *) SHMQueuePrev(&(WalSndCtl->SyncRepQueue[mode]),
|
|
|
|
&(WalSndCtl->SyncRepQueue[mode]),
|
2011-03-07 00:39:14 +01:00
|
|
|
offsetof(PGPROC, syncRepLinks));
|
|
|
|
|
|
|
|
while (proc)
|
|
|
|
{
|
|
|
|
/*
|
2011-04-10 17:42:00 +02:00
|
|
|
* Stop at the queue element that we should after to ensure the queue
|
|
|
|
* is ordered by LSN.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2012-12-28 17:06:15 +01:00
|
|
|
if (proc->waitLSN < MyProc->waitLSN)
|
2011-03-07 00:39:14 +01:00
|
|
|
break;
|
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
proc = (PGPROC *) SHMQueuePrev(&(WalSndCtl->SyncRepQueue[mode]),
|
2011-03-07 00:39:14 +01:00
|
|
|
&(proc->syncRepLinks),
|
|
|
|
offsetof(PGPROC, syncRepLinks));
|
|
|
|
}
|
|
|
|
|
|
|
|
if (proc)
|
|
|
|
SHMQueueInsertAfter(&(proc->syncRepLinks), &(MyProc->syncRepLinks));
|
|
|
|
else
|
2012-01-24 21:22:37 +01:00
|
|
|
SHMQueueInsertAfter(&(WalSndCtl->SyncRepQueue[mode]), &(MyProc->syncRepLinks));
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
|
|
|
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
/*
|
|
|
|
* Acquire SyncRepLock and cancel any wait currently in progress.
|
|
|
|
*/
|
|
|
|
static void
|
|
|
|
SyncRepCancelWait(void)
|
|
|
|
{
|
|
|
|
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
|
|
|
|
if (!SHMQueueIsDetached(&(MyProc->syncRepLinks)))
|
|
|
|
SHMQueueDelete(&(MyProc->syncRepLinks));
|
|
|
|
MyProc->syncRepState = SYNC_REP_NOT_WAITING;
|
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
}
|
|
|
|
|
2011-03-07 00:39:14 +01:00
|
|
|
void
|
2011-08-10 18:20:30 +02:00
|
|
|
SyncRepCleanupAtProcExit(void)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
|
|
|
if (!SHMQueueIsDetached(&(MyProc->syncRepLinks)))
|
|
|
|
{
|
|
|
|
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
|
|
|
|
SHMQueueDelete(&(MyProc->syncRepLinks));
|
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ===========================================================
|
|
|
|
* Synchronous Replication functions for wal sender processes
|
|
|
|
* ===========================================================
|
|
|
|
*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Take any action required to initialise sync rep state from config
|
|
|
|
* data. Called at WALSender startup and after each SIGHUP.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
SyncRepInitConfig(void)
|
|
|
|
{
|
2011-04-10 17:42:00 +02:00
|
|
|
int priority;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Determine if we are a potential sync standby and remember the result
|
|
|
|
* for handling replies from standby.
|
|
|
|
*/
|
|
|
|
priority = SyncRepGetStandbyPriority();
|
|
|
|
if (MyWalSnd->sync_standby_priority != priority)
|
|
|
|
{
|
|
|
|
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
|
|
|
|
MyWalSnd->sync_standby_priority = priority;
|
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
ereport(DEBUG1,
|
Phase 3 of pgindent updates.
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 21:35:54 +02:00
|
|
|
(errmsg("standby \"%s\" now has synchronous standby priority %u",
|
|
|
|
application_name, priority)));
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Update the LSNs on each queue based upon our latest state. This
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
* implements a simple policy of first-valid-sync-standby-releases-waiter.
|
2011-03-07 00:39:14 +01:00
|
|
|
*
|
2016-02-29 22:11:58 +01:00
|
|
|
* Other policies are possible, which would change what we do here and
|
2011-03-07 00:39:14 +01:00
|
|
|
* perhaps also which information we store as well.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
SyncRepReleaseWaiters(void)
|
|
|
|
{
|
|
|
|
volatile WalSndCtlData *walsndctl = WalSndCtl;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
XLogRecPtr writePtr;
|
|
|
|
XLogRecPtr flushPtr;
|
|
|
|
XLogRecPtr applyPtr;
|
2016-12-19 13:15:30 +01:00
|
|
|
bool got_recptr;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
bool am_sync;
|
2012-01-24 21:22:37 +01:00
|
|
|
int numwrite = 0;
|
|
|
|
int numflush = 0;
|
2016-03-30 03:16:12 +02:00
|
|
|
int numapply = 0;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* If this WALSender is serving a standby that is not on the list of
|
2016-02-29 22:11:58 +01:00
|
|
|
* potential sync standbys then we have nothing to do. If we are still
|
2016-06-10 00:02:36 +02:00
|
|
|
* starting up, still running base backup or the current flush position is
|
|
|
|
* still invalid, then leave quickly also.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
|
|
|
if (MyWalSnd->sync_standby_priority == 0 ||
|
2012-07-04 15:10:46 +02:00
|
|
|
MyWalSnd->state < WALSNDSTATE_STREAMING ||
|
|
|
|
XLogRecPtrIsInvalid(MyWalSnd->flush))
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
{
|
|
|
|
announce_next_takeover = true;
|
2011-03-07 00:39:14 +01:00
|
|
|
return;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
}
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
2016-06-10 00:02:36 +02:00
|
|
|
* We're a potential sync standby. Release waiters if there are enough
|
|
|
|
* sync standbys and we are considered as sync.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
|
|
|
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
|
|
|
|
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
/*
|
2016-12-19 13:15:30 +01:00
|
|
|
* Check whether we are a sync standby or not, and calculate the synced
|
2016-06-10 00:02:36 +02:00
|
|
|
* positions among all sync standbys.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
2016-12-19 13:15:30 +01:00
|
|
|
got_recptr = SyncRepGetSyncRecPtr(&writePtr, &flushPtr, &applyPtr, &am_sync);
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
|
|
|
/*
|
2016-06-10 00:02:36 +02:00
|
|
|
* If we are managing a sync standby, though we weren't prior to this,
|
|
|
|
* then announce we are now a sync standby.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
if (announce_next_takeover && am_sync)
|
|
|
|
{
|
|
|
|
announce_next_takeover = false;
|
2016-12-19 13:15:30 +01:00
|
|
|
|
|
|
|
if (SyncRepConfig->syncrep_method == SYNC_REP_PRIORITY)
|
|
|
|
ereport(LOG,
|
|
|
|
(errmsg("standby \"%s\" is now a synchronous standby with priority %u",
|
Phase 3 of pgindent updates.
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 21:35:54 +02:00
|
|
|
application_name, MyWalSnd->sync_standby_priority)));
|
2016-12-19 13:15:30 +01:00
|
|
|
else
|
|
|
|
ereport(LOG,
|
|
|
|
(errmsg("standby \"%s\" is now a candidate for quorum synchronous standby",
|
|
|
|
application_name)));
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
}
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
* If the number of sync standbys is less than requested or we aren't
|
|
|
|
* managing a sync standby then just leave.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2016-12-19 13:15:30 +01:00
|
|
|
if (!got_recptr || !am_sync)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
|
|
|
LWLockRelease(SyncRepLock);
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
announce_next_takeover = !am_sync;
|
2011-03-07 00:39:14 +01:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
/*
|
2012-06-10 21:20:04 +02:00
|
|
|
* Set the lsn first so that when we wake backends they will release up to
|
|
|
|
* this location.
|
2012-01-24 21:22:37 +01:00
|
|
|
*/
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
|
2012-01-24 21:22:37 +01:00
|
|
|
numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
|
|
|
|
}
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
|
2012-01-24 21:22:37 +01:00
|
|
|
{
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
|
2012-01-24 21:22:37 +01:00
|
|
|
numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
|
2016-03-30 03:16:12 +02:00
|
|
|
{
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
|
2016-03-30 03:16:12 +02:00
|
|
|
numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
|
|
|
|
}
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
|
2016-04-06 15:20:52 +02:00
|
|
|
elog(DEBUG3, "released %d procs up to write %X/%X, %d procs up to flush %X/%X, %d procs up to apply %X/%X",
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
numwrite, (uint32) (writePtr >> 32), (uint32) writePtr,
|
|
|
|
numflush, (uint32) (flushPtr >> 32), (uint32) flushPtr,
|
|
|
|
numapply, (uint32) (applyPtr >> 32), (uint32) applyPtr);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2016-12-19 13:15:30 +01:00
|
|
|
* Calculate the synced Write, Flush and Apply positions among sync standbys.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*
|
|
|
|
* Return false if the number of sync standbys is less than
|
|
|
|
* synchronous_standby_names specifies. Otherwise return true and
|
2016-12-19 13:15:30 +01:00
|
|
|
* store the positions into *writePtr, *flushPtr and *applyPtr.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*
|
|
|
|
* On return, *am_sync is set to true if this walsender is connecting to
|
|
|
|
* sync standby. Otherwise it's set to false.
|
|
|
|
*/
|
|
|
|
static bool
|
2016-12-19 13:15:30 +01:00
|
|
|
SyncRepGetSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr,
|
2017-05-17 22:31:56 +02:00
|
|
|
XLogRecPtr *applyPtr, bool *am_sync)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
{
|
2016-06-10 00:02:36 +02:00
|
|
|
List *sync_standbys;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
|
|
|
*writePtr = InvalidXLogRecPtr;
|
|
|
|
*flushPtr = InvalidXLogRecPtr;
|
|
|
|
*applyPtr = InvalidXLogRecPtr;
|
|
|
|
*am_sync = false;
|
|
|
|
|
|
|
|
/* Get standbys that are considered as synchronous at this moment */
|
|
|
|
sync_standbys = SyncRepGetSyncStandbys(am_sync);
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
* Quick exit if we are not managing a sync standby or there are not
|
|
|
|
* enough synchronous standbys.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
if (!(*am_sync) ||
|
|
|
|
SyncRepConfig == NULL ||
|
|
|
|
list_length(sync_standbys) < SyncRepConfig->num_sync)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
list_free(sync_standbys);
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2016-12-19 13:15:30 +01:00
|
|
|
* In a priority-based sync replication, the synced positions are the
|
|
|
|
* oldest ones among sync standbys. In a quorum-based, they are the Nth
|
|
|
|
* latest ones.
|
|
|
|
*
|
2017-05-17 22:31:56 +02:00
|
|
|
* SyncRepGetNthLatestSyncRecPtr() also can calculate the oldest
|
|
|
|
* positions. But we use SyncRepGetOldestSyncRecPtr() for that calculation
|
|
|
|
* because it's a bit more efficient.
|
2016-12-19 13:15:30 +01:00
|
|
|
*
|
|
|
|
* XXX If the numbers of current and requested sync standbys are the same,
|
|
|
|
* we can use SyncRepGetOldestSyncRecPtr() to calculate the synced
|
|
|
|
* positions even in a quorum-based sync replication.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
2016-12-19 13:15:30 +01:00
|
|
|
if (SyncRepConfig->syncrep_method == SYNC_REP_PRIORITY)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
{
|
2016-12-19 13:15:30 +01:00
|
|
|
SyncRepGetOldestSyncRecPtr(writePtr, flushPtr, applyPtr,
|
|
|
|
sync_standbys);
|
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
SyncRepGetNthLatestSyncRecPtr(writePtr, flushPtr, applyPtr,
|
|
|
|
sync_standbys, SyncRepConfig->num_sync);
|
|
|
|
}
|
|
|
|
|
|
|
|
list_free(sync_standbys);
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Calculate the oldest Write, Flush and Apply positions among sync standbys.
|
|
|
|
*/
|
|
|
|
static void
|
|
|
|
SyncRepGetOldestSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr,
|
|
|
|
XLogRecPtr *applyPtr, List *sync_standbys)
|
|
|
|
{
|
2017-05-17 22:31:56 +02:00
|
|
|
ListCell *cell;
|
2016-12-19 13:15:30 +01:00
|
|
|
|
|
|
|
/*
|
2017-05-17 22:31:56 +02:00
|
|
|
* Scan through all sync standbys and calculate the oldest Write, Flush
|
|
|
|
* and Apply positions.
|
2016-12-19 13:15:30 +01:00
|
|
|
*/
|
2017-05-17 22:31:56 +02:00
|
|
|
foreach(cell, sync_standbys)
|
2016-12-19 13:15:30 +01:00
|
|
|
{
|
2017-05-17 22:31:56 +02:00
|
|
|
WalSnd *walsnd = &WalSndCtl->walsnds[lfirst_int(cell)];
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
XLogRecPtr write;
|
|
|
|
XLogRecPtr flush;
|
|
|
|
XLogRecPtr apply;
|
|
|
|
|
|
|
|
SpinLockAcquire(&walsnd->mutex);
|
|
|
|
write = walsnd->write;
|
|
|
|
flush = walsnd->flush;
|
|
|
|
apply = walsnd->apply;
|
|
|
|
SpinLockRelease(&walsnd->mutex);
|
|
|
|
|
|
|
|
if (XLogRecPtrIsInvalid(*writePtr) || *writePtr > write)
|
|
|
|
*writePtr = write;
|
|
|
|
if (XLogRecPtrIsInvalid(*flushPtr) || *flushPtr > flush)
|
|
|
|
*flushPtr = flush;
|
|
|
|
if (XLogRecPtrIsInvalid(*applyPtr) || *applyPtr > apply)
|
|
|
|
*applyPtr = apply;
|
|
|
|
}
|
2016-12-19 13:15:30 +01:00
|
|
|
}
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
2016-12-19 13:15:30 +01:00
|
|
|
/*
|
|
|
|
* Calculate the Nth latest Write, Flush and Apply positions among sync
|
|
|
|
* standbys.
|
|
|
|
*/
|
|
|
|
static void
|
|
|
|
SyncRepGetNthLatestSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr,
|
Phase 3 of pgindent updates.
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 21:35:54 +02:00
|
|
|
XLogRecPtr *applyPtr, List *sync_standbys, uint8 nth)
|
2016-12-19 13:15:30 +01:00
|
|
|
{
|
2017-05-17 22:31:56 +02:00
|
|
|
ListCell *cell;
|
|
|
|
XLogRecPtr *write_array;
|
|
|
|
XLogRecPtr *flush_array;
|
|
|
|
XLogRecPtr *apply_array;
|
|
|
|
int len;
|
|
|
|
int i = 0;
|
2016-12-19 13:15:30 +01:00
|
|
|
|
|
|
|
len = list_length(sync_standbys);
|
|
|
|
write_array = (XLogRecPtr *) palloc(sizeof(XLogRecPtr) * len);
|
|
|
|
flush_array = (XLogRecPtr *) palloc(sizeof(XLogRecPtr) * len);
|
|
|
|
apply_array = (XLogRecPtr *) palloc(sizeof(XLogRecPtr) * len);
|
|
|
|
|
2017-05-17 22:31:56 +02:00
|
|
|
foreach(cell, sync_standbys)
|
2016-12-19 13:15:30 +01:00
|
|
|
{
|
2017-05-17 22:31:56 +02:00
|
|
|
WalSnd *walsnd = &WalSndCtl->walsnds[lfirst_int(cell)];
|
2016-12-19 13:15:30 +01:00
|
|
|
|
|
|
|
SpinLockAcquire(&walsnd->mutex);
|
|
|
|
write_array[i] = walsnd->write;
|
|
|
|
flush_array[i] = walsnd->flush;
|
|
|
|
apply_array[i] = walsnd->apply;
|
|
|
|
SpinLockRelease(&walsnd->mutex);
|
|
|
|
|
|
|
|
i++;
|
|
|
|
}
|
|
|
|
|
2017-04-18 19:58:28 +02:00
|
|
|
/* Sort each array in descending order */
|
2016-12-19 13:15:30 +01:00
|
|
|
qsort(write_array, len, sizeof(XLogRecPtr), cmp_lsn);
|
|
|
|
qsort(flush_array, len, sizeof(XLogRecPtr), cmp_lsn);
|
|
|
|
qsort(apply_array, len, sizeof(XLogRecPtr), cmp_lsn);
|
|
|
|
|
|
|
|
/* Get Nth latest Write, Flush, Apply positions */
|
|
|
|
*writePtr = write_array[nth - 1];
|
|
|
|
*flushPtr = flush_array[nth - 1];
|
|
|
|
*applyPtr = apply_array[nth - 1];
|
|
|
|
|
|
|
|
pfree(write_array);
|
|
|
|
pfree(flush_array);
|
|
|
|
pfree(apply_array);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Compare lsn in order to sort array in descending order.
|
|
|
|
*/
|
|
|
|
static int
|
|
|
|
cmp_lsn(const void *a, const void *b)
|
|
|
|
{
|
2017-05-17 22:31:56 +02:00
|
|
|
XLogRecPtr lsn1 = *((const XLogRecPtr *) a);
|
|
|
|
XLogRecPtr lsn2 = *((const XLogRecPtr *) b);
|
2016-12-19 13:15:30 +01:00
|
|
|
|
|
|
|
if (lsn1 > lsn2)
|
|
|
|
return -1;
|
|
|
|
else if (lsn1 == lsn2)
|
|
|
|
return 0;
|
|
|
|
else
|
|
|
|
return 1;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Return the list of sync standbys, or NIL if no sync standby is connected.
|
|
|
|
*
|
|
|
|
* The caller must hold SyncRepLock.
|
|
|
|
*
|
|
|
|
* On return, *am_sync is set to true if this walsender is connecting to
|
|
|
|
* sync standby. Otherwise it's set to false.
|
|
|
|
*/
|
|
|
|
List *
|
2017-05-17 22:31:56 +02:00
|
|
|
SyncRepGetSyncStandbys(bool *am_sync)
|
2016-12-19 13:15:30 +01:00
|
|
|
{
|
|
|
|
/* Set default result */
|
|
|
|
if (am_sync != NULL)
|
|
|
|
*am_sync = false;
|
|
|
|
|
|
|
|
/* Quick exit if sync replication is not requested */
|
|
|
|
if (SyncRepConfig == NULL)
|
|
|
|
return NIL;
|
|
|
|
|
|
|
|
return (SyncRepConfig->syncrep_method == SYNC_REP_PRIORITY) ?
|
|
|
|
SyncRepGetSyncStandbysPriority(am_sync) :
|
|
|
|
SyncRepGetSyncStandbysQuorum(am_sync);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Return the list of all the candidates for quorum sync standbys,
|
|
|
|
* or NIL if no such standby is connected.
|
|
|
|
*
|
|
|
|
* The caller must hold SyncRepLock. This function must be called only in
|
|
|
|
* a quorum-based sync replication.
|
|
|
|
*
|
|
|
|
* On return, *am_sync is set to true if this walsender is connecting to
|
|
|
|
* sync standby. Otherwise it's set to false.
|
|
|
|
*/
|
|
|
|
static List *
|
|
|
|
SyncRepGetSyncStandbysQuorum(bool *am_sync)
|
|
|
|
{
|
2017-05-17 22:31:56 +02:00
|
|
|
List *result = NIL;
|
|
|
|
int i;
|
2016-12-19 13:15:30 +01:00
|
|
|
volatile WalSnd *walsnd; /* Use volatile pointer to prevent code
|
|
|
|
* rearrangement */
|
|
|
|
|
|
|
|
Assert(SyncRepConfig->syncrep_method == SYNC_REP_QUORUM);
|
|
|
|
|
|
|
|
for (i = 0; i < max_wal_senders; i++)
|
|
|
|
{
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
XLogRecPtr flush;
|
2017-08-14 23:29:33 +02:00
|
|
|
WalSndState state;
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
int pid;
|
|
|
|
|
2016-12-19 13:15:30 +01:00
|
|
|
walsnd = &WalSndCtl->walsnds[i];
|
|
|
|
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
SpinLockAcquire(&walsnd->mutex);
|
|
|
|
pid = walsnd->pid;
|
|
|
|
flush = walsnd->flush;
|
|
|
|
state = walsnd->state;
|
|
|
|
SpinLockRelease(&walsnd->mutex);
|
|
|
|
|
2016-12-19 13:15:30 +01:00
|
|
|
/* Must be active */
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
if (pid == 0)
|
2016-12-19 13:15:30 +01:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Must be streaming */
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
if (state != WALSNDSTATE_STREAMING)
|
2016-12-19 13:15:30 +01:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Must be synchronous */
|
|
|
|
if (walsnd->sync_standby_priority == 0)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Must have a valid flush position */
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
if (XLogRecPtrIsInvalid(flush))
|
2016-12-19 13:15:30 +01:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/*
|
2017-05-17 22:31:56 +02:00
|
|
|
* Consider this standby as a candidate for quorum sync standbys and
|
|
|
|
* append it to the result.
|
2016-12-19 13:15:30 +01:00
|
|
|
*/
|
|
|
|
result = lappend_int(result, i);
|
|
|
|
if (am_sync != NULL && walsnd == MyWalSnd)
|
|
|
|
*am_sync = true;
|
|
|
|
}
|
|
|
|
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Return the list of sync standbys chosen based on their priorities,
|
|
|
|
* or NIL if no sync standby is connected.
|
|
|
|
*
|
|
|
|
* If there are multiple standbys with the same priority,
|
|
|
|
* the first one found is selected preferentially.
|
|
|
|
*
|
|
|
|
* The caller must hold SyncRepLock. This function must be called only in
|
|
|
|
* a priority-based sync replication.
|
|
|
|
*
|
|
|
|
* On return, *am_sync is set to true if this walsender is connecting to
|
|
|
|
* sync standby. Otherwise it's set to false.
|
|
|
|
*/
|
|
|
|
static List *
|
|
|
|
SyncRepGetSyncStandbysPriority(bool *am_sync)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
{
|
2016-06-10 00:02:36 +02:00
|
|
|
List *result = NIL;
|
|
|
|
List *pending = NIL;
|
|
|
|
int lowest_priority;
|
|
|
|
int next_highest_priority;
|
|
|
|
int this_priority;
|
|
|
|
int priority;
|
|
|
|
int i;
|
|
|
|
bool am_in_pending = false;
|
|
|
|
volatile WalSnd *walsnd; /* Use volatile pointer to prevent code
|
|
|
|
* rearrangement */
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
2016-12-19 13:15:30 +01:00
|
|
|
Assert(SyncRepConfig->syncrep_method == SYNC_REP_PRIORITY);
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
lowest_priority = SyncRepConfig->nmembers;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
next_highest_priority = lowest_priority + 1;
|
|
|
|
|
|
|
|
/*
|
2016-06-10 00:02:36 +02:00
|
|
|
* Find the sync standbys which have the highest priority (i.e, 1). Also
|
|
|
|
* store all the other potential sync standbys into the pending list, in
|
|
|
|
* order to scan it later and find other sync standbys from it quickly.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
for (i = 0; i < max_wal_senders; i++)
|
|
|
|
{
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
XLogRecPtr flush;
|
2017-08-14 23:29:33 +02:00
|
|
|
WalSndState state;
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
int pid;
|
|
|
|
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
walsnd = &WalSndCtl->walsnds[i];
|
|
|
|
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
SpinLockAcquire(&walsnd->mutex);
|
|
|
|
pid = walsnd->pid;
|
|
|
|
flush = walsnd->flush;
|
|
|
|
state = walsnd->state;
|
|
|
|
SpinLockRelease(&walsnd->mutex);
|
|
|
|
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
/* Must be active */
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
if (pid == 0)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Must be streaming */
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
if (state != WALSNDSTATE_STREAMING)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Must be synchronous */
|
|
|
|
this_priority = walsnd->sync_standby_priority;
|
|
|
|
if (this_priority == 0)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Must have a valid flush position */
|
Fix locking in WAL receiver/sender shmem state structs
In WAL receiver and WAL server, some accesses to their corresponding
shared memory control structs were done without holding any kind of
lock, which could lead to inconsistent and possibly insecure results.
In walsender, fix by clarifying the locking rules and following them
correctly, as documented in the new comment in walsender_private.h;
namely that some members can be read in walsender itself without a lock,
because the only writes occur in the same process. The rest of the
struct requires spinlock for accesses, as usual.
In walreceiver, fix by always holding spinlock while accessing the
struct.
While there is potentially a problem in all branches, it is minor in
stable ones. This only became a real problem in pg10 because of quorum
commit in synchronous replication (commit 3901fd70cc7c), and a potential
security problem in walreceiver because a superuser() check was removed
by default monitoring roles (commit 25fff40798fc). Thus, no backpatch.
In passing, clean up some leftover braces which were used to create
unconditional blocks. Once upon a time these were used for
volatile-izing accesses to those shmem structs, which is no longer
required. Many other occurrences of this pattern remain.
Author: Michaël Paquier
Reported-by: Michaël Paquier
Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro,
Robert Haas
Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-07-01 00:06:33 +02:00
|
|
|
if (XLogRecPtrIsInvalid(flush))
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/*
|
2016-06-10 00:02:36 +02:00
|
|
|
* If the priority is equal to 1, consider this standby as sync and
|
|
|
|
* append it to the result. Otherwise append this standby to the
|
|
|
|
* pending list to check if it's actually sync or not later.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
if (this_priority == 1)
|
|
|
|
{
|
|
|
|
result = lappend_int(result, i);
|
|
|
|
if (am_sync != NULL && walsnd == MyWalSnd)
|
|
|
|
*am_sync = true;
|
|
|
|
if (list_length(result) == SyncRepConfig->num_sync)
|
|
|
|
{
|
|
|
|
list_free(pending);
|
2016-06-10 00:02:36 +02:00
|
|
|
return result; /* Exit if got enough sync standbys */
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
}
|
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
pending = lappend_int(pending, i);
|
|
|
|
if (am_sync != NULL && walsnd == MyWalSnd)
|
|
|
|
am_in_pending = true;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Track the highest priority among the standbys in the pending
|
2016-06-10 00:02:36 +02:00
|
|
|
* list, in order to use it as the starting priority for later
|
|
|
|
* scan of the list. This is useful to find quickly the sync
|
|
|
|
* standbys from the pending list later because we can skip
|
|
|
|
* unnecessary scans for the unused priorities.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
if (this_priority < next_highest_priority)
|
|
|
|
next_highest_priority = this_priority;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Consider all pending standbys as sync if the number of them plus
|
|
|
|
* already-found sync ones is lower than the configuration requests.
|
|
|
|
*/
|
|
|
|
if (list_length(result) + list_length(pending) <= SyncRepConfig->num_sync)
|
|
|
|
{
|
|
|
|
bool needfree = (result != NIL && pending != NIL);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Set *am_sync to true if this walsender is in the pending list
|
|
|
|
* because all pending standbys are considered as sync.
|
|
|
|
*/
|
|
|
|
if (am_sync != NULL && !(*am_sync))
|
|
|
|
*am_sync = am_in_pending;
|
|
|
|
|
|
|
|
result = list_concat(result, pending);
|
|
|
|
if (needfree)
|
|
|
|
pfree(pending);
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Find the sync standbys from the pending list.
|
|
|
|
*/
|
|
|
|
priority = next_highest_priority;
|
|
|
|
while (priority <= lowest_priority)
|
|
|
|
{
|
2016-06-10 00:02:36 +02:00
|
|
|
ListCell *cell;
|
|
|
|
ListCell *prev = NULL;
|
|
|
|
ListCell *next;
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
|
|
|
next_highest_priority = lowest_priority + 1;
|
|
|
|
|
|
|
|
for (cell = list_head(pending); cell != NULL; cell = next)
|
|
|
|
{
|
|
|
|
i = lfirst_int(cell);
|
|
|
|
walsnd = &WalSndCtl->walsnds[i];
|
|
|
|
|
|
|
|
next = lnext(cell);
|
|
|
|
|
|
|
|
this_priority = walsnd->sync_standby_priority;
|
|
|
|
if (this_priority == priority)
|
|
|
|
{
|
|
|
|
result = lappend_int(result, i);
|
|
|
|
if (am_sync != NULL && walsnd == MyWalSnd)
|
|
|
|
*am_sync = true;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We should always exit here after the scan of pending list
|
2016-06-10 00:02:36 +02:00
|
|
|
* starts because we know that the list has enough elements to
|
|
|
|
* reach SyncRepConfig->num_sync.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
if (list_length(result) == SyncRepConfig->num_sync)
|
|
|
|
{
|
|
|
|
list_free(pending);
|
Phase 2 of pgindent updates.
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 21:18:54 +02:00
|
|
|
return result; /* Exit if got enough sync standbys */
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2016-06-10 00:02:36 +02:00
|
|
|
* Remove the entry for this sync standby from the list to
|
|
|
|
* prevent us from looking at the same entry again.
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
pending = list_delete_cell(pending, cell, prev);
|
|
|
|
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (this_priority < next_highest_priority)
|
|
|
|
next_highest_priority = this_priority;
|
|
|
|
|
|
|
|
prev = cell;
|
|
|
|
}
|
|
|
|
|
|
|
|
priority = next_highest_priority;
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
|
|
|
|
/* never reached, but keep compiler quiet */
|
|
|
|
Assert(false);
|
|
|
|
return result;
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Check if we are in the list of sync standbys, and if so, determine
|
|
|
|
* priority sequence. Return priority if set, or zero to indicate that
|
|
|
|
* we are not a potential sync standby.
|
|
|
|
*
|
|
|
|
* Compare the parameter SyncRepStandbyNames against the application_name
|
|
|
|
* for this WALSender, or allow any name if we find a wildcard "*".
|
|
|
|
*/
|
|
|
|
static int
|
|
|
|
SyncRepGetStandbyPriority(void)
|
|
|
|
{
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
const char *standby_name;
|
|
|
|
int priority;
|
2011-03-07 00:39:14 +01:00
|
|
|
bool found = false;
|
|
|
|
|
2011-07-19 04:40:03 +02:00
|
|
|
/*
|
2012-06-10 21:20:04 +02:00
|
|
|
* Since synchronous cascade replication is not allowed, we always set the
|
|
|
|
* priority of cascading walsender to zero.
|
2011-07-19 04:40:03 +02:00
|
|
|
*/
|
|
|
|
if (am_cascading_walsender)
|
|
|
|
return 0;
|
|
|
|
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
if (!SyncStandbysDefined() || SyncRepConfig == NULL)
|
2011-03-07 00:39:14 +01:00
|
|
|
return 0;
|
|
|
|
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
standby_name = SyncRepConfig->member_names;
|
|
|
|
for (priority = 1; priority <= SyncRepConfig->nmembers; priority++)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
|
|
|
if (pg_strcasecmp(standby_name, application_name) == 0 ||
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
strcmp(standby_name, "*") == 0)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
|
|
|
found = true;
|
|
|
|
break;
|
|
|
|
}
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
standby_name += strlen(standby_name) + 1;
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
|
|
|
|
2017-04-25 18:07:13 +02:00
|
|
|
if (!found)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
/*
|
2017-05-17 22:31:56 +02:00
|
|
|
* In quorum-based sync replication, all the standbys in the list have the
|
|
|
|
* same priority, one.
|
2017-04-25 18:07:13 +02:00
|
|
|
*/
|
|
|
|
return (SyncRepConfig->syncrep_method == SYNC_REP_PRIORITY) ? priority : 1;
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2014-05-06 18:12:18 +02:00
|
|
|
* Walk the specified queue from head. Set the state of any backends that
|
2012-01-24 21:22:37 +01:00
|
|
|
* need to be woken, remove them from the queue, and then wake them.
|
|
|
|
* Pass all = true to wake whole queue; otherwise, just wake up to
|
|
|
|
* the walsender's LSN.
|
2011-03-07 00:39:14 +01:00
|
|
|
*
|
|
|
|
* Must hold SyncRepLock.
|
|
|
|
*/
|
2015-03-26 02:34:08 +01:00
|
|
|
static int
|
2012-01-24 21:22:37 +01:00
|
|
|
SyncRepWakeQueue(bool all, int mode)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
|
|
|
volatile WalSndCtlData *walsndctl = WalSndCtl;
|
2011-04-10 17:42:00 +02:00
|
|
|
PGPROC *proc = NULL;
|
|
|
|
PGPROC *thisproc = NULL;
|
|
|
|
int numprocs = 0;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);
|
|
|
|
Assert(SyncRepQueueIsOrderedByLSN(mode));
|
2011-03-07 00:39:14 +01:00
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
|
|
|
|
&(WalSndCtl->SyncRepQueue[mode]),
|
2011-03-07 00:39:14 +01:00
|
|
|
offsetof(PGPROC, syncRepLinks));
|
|
|
|
|
|
|
|
while (proc)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* Assume the queue is ordered by LSN
|
|
|
|
*/
|
2012-12-28 17:06:15 +01:00
|
|
|
if (!all && walsndctl->lsn[mode] < proc->waitLSN)
|
2011-03-07 00:39:14 +01:00
|
|
|
return numprocs;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Move to next proc, so we can delete thisproc from the queue.
|
|
|
|
* thisproc is valid, proc may be NULL after this.
|
|
|
|
*/
|
|
|
|
thisproc = proc;
|
2012-01-24 21:22:37 +01:00
|
|
|
proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
|
2011-03-07 00:39:14 +01:00
|
|
|
&(proc->syncRepLinks),
|
|
|
|
offsetof(PGPROC, syncRepLinks));
|
|
|
|
|
|
|
|
/*
|
2017-07-12 14:30:52 +02:00
|
|
|
* Remove thisproc from queue.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2017-07-12 14:30:52 +02:00
|
|
|
SHMQueueDelete(&(thisproc->syncRepLinks));
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
2017-07-12 14:30:52 +02:00
|
|
|
* SyncRepWaitForLSN() reads syncRepState without holding the lock, so
|
|
|
|
* make sure that it sees the queue link being removed before the
|
|
|
|
* syncRepState change.
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2017-07-12 14:30:52 +02:00
|
|
|
pg_write_barrier();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Set state to complete; see SyncRepWaitForLSN() for discussion of
|
|
|
|
* the various states.
|
|
|
|
*/
|
|
|
|
thisproc->syncRepState = SYNC_REP_WAIT_COMPLETE;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Wake only when we have set state and removed from queue.
|
|
|
|
*/
|
2011-08-10 18:20:30 +02:00
|
|
|
SetLatch(&(thisproc->procLatch));
|
2011-03-07 00:39:14 +01:00
|
|
|
|
|
|
|
numprocs++;
|
|
|
|
}
|
|
|
|
|
|
|
|
return numprocs;
|
|
|
|
}
|
|
|
|
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
/*
|
2012-01-30 15:34:25 +01:00
|
|
|
* The checkpointer calls this as needed to update the shared
|
2011-03-19 02:43:45 +01:00
|
|
|
* sync_standbys_defined flag, so that backends don't remain permanently wedged
|
|
|
|
* if synchronous_standby_names is unset. It's safe to check the current value
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
* without the lock, because it's only ever updated by one process. But we
|
|
|
|
* must take the lock to change it.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
SyncRepUpdateSyncStandbysDefined(void)
|
|
|
|
{
|
|
|
|
bool sync_standbys_defined = SyncStandbysDefined();
|
|
|
|
|
|
|
|
if (sync_standbys_defined != WalSndCtl->sync_standbys_defined)
|
|
|
|
{
|
|
|
|
LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If synchronous_standby_names has been reset to empty, it's futile
|
|
|
|
* for backends to continue to waiting. Since the user no longer
|
|
|
|
* wants synchronous replication, we'd better wake them up.
|
|
|
|
*/
|
|
|
|
if (!sync_standbys_defined)
|
2012-01-24 21:22:37 +01:00
|
|
|
{
|
2012-06-10 21:20:04 +02:00
|
|
|
int i;
|
2012-01-24 21:22:37 +01:00
|
|
|
|
|
|
|
for (i = 0; i < NUM_SYNC_REP_WAIT_MODE; i++)
|
|
|
|
SyncRepWakeQueue(true, i);
|
|
|
|
}
|
Fix various possible problems with synchronous replication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
2011-03-17 18:10:42 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Only allow people to join the queue when there are synchronous
|
|
|
|
* standbys defined. Without this interlock, there's a race
|
|
|
|
* condition: we might wake up all the current waiters; then, some
|
|
|
|
* backend that hasn't yet reloaded its config might go to sleep on
|
|
|
|
* the queue (and never wake up). This prevents that.
|
|
|
|
*/
|
|
|
|
WalSndCtl->sync_standbys_defined = sync_standbys_defined;
|
|
|
|
|
|
|
|
LWLockRelease(SyncRepLock);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-03-07 00:39:14 +01:00
|
|
|
#ifdef USE_ASSERT_CHECKING
|
|
|
|
static bool
|
2012-01-24 21:22:37 +01:00
|
|
|
SyncRepQueueIsOrderedByLSN(int mode)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
2011-04-10 17:42:00 +02:00
|
|
|
PGPROC *proc = NULL;
|
|
|
|
XLogRecPtr lastLSN;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);
|
|
|
|
|
2012-06-24 17:51:37 +02:00
|
|
|
lastLSN = 0;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
|
|
|
|
&(WalSndCtl->SyncRepQueue[mode]),
|
2011-03-07 00:39:14 +01:00
|
|
|
offsetof(PGPROC, syncRepLinks));
|
|
|
|
|
|
|
|
while (proc)
|
|
|
|
{
|
|
|
|
/*
|
2011-04-10 17:42:00 +02:00
|
|
|
* Check the queue is ordered by LSN and that multiple procs don't
|
|
|
|
* have matching LSNs
|
2011-03-07 00:39:14 +01:00
|
|
|
*/
|
2012-12-28 17:06:15 +01:00
|
|
|
if (proc->waitLSN <= lastLSN)
|
2011-03-07 00:39:14 +01:00
|
|
|
return false;
|
|
|
|
|
|
|
|
lastLSN = proc->waitLSN;
|
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
|
2011-03-07 00:39:14 +01:00
|
|
|
&(proc->syncRepLinks),
|
|
|
|
offsetof(PGPROC, syncRepLinks));
|
|
|
|
}
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ===========================================================
|
|
|
|
* Synchronous Replication functions executed by any process
|
|
|
|
* ===========================================================
|
|
|
|
*/
|
|
|
|
|
2011-04-07 06:11:01 +02:00
|
|
|
bool
|
|
|
|
check_synchronous_standby_names(char **newval, void **extra, GucSource source)
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
if (*newval != NULL && (*newval)[0] != '\0')
|
2011-03-07 00:39:14 +01:00
|
|
|
{
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
int parse_rc;
|
|
|
|
SyncRepConfigData *pconf;
|
|
|
|
|
|
|
|
/* Reset communication variables to ensure a fresh start */
|
|
|
|
syncrep_parse_result = NULL;
|
|
|
|
syncrep_parse_error_msg = NULL;
|
|
|
|
|
|
|
|
/* Parse the synchronous_standby_names string */
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
syncrep_scanner_init(*newval);
|
|
|
|
parse_rc = syncrep_yyparse();
|
|
|
|
syncrep_scanner_finish();
|
2011-03-07 00:39:14 +01:00
|
|
|
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
if (parse_rc != 0 || syncrep_parse_result == NULL)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
{
|
|
|
|
GUC_check_errcode(ERRCODE_SYNTAX_ERROR);
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
if (syncrep_parse_error_msg)
|
|
|
|
GUC_check_errdetail("%s", syncrep_parse_error_msg);
|
|
|
|
else
|
|
|
|
GUC_check_errdetail("synchronous_standby_names parser failed");
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
2016-12-16 18:20:59 +01:00
|
|
|
if (syncrep_parse_result->num_sync <= 0)
|
|
|
|
{
|
|
|
|
GUC_check_errmsg("number of synchronous standbys (%d) must be greater than zero",
|
|
|
|
syncrep_parse_result->num_sync);
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
/* GUC extra value must be malloc'd, not palloc'd */
|
|
|
|
pconf = (SyncRepConfigData *)
|
|
|
|
malloc(syncrep_parse_result->config_size);
|
|
|
|
if (pconf == NULL)
|
|
|
|
return false;
|
|
|
|
memcpy(pconf, syncrep_parse_result, syncrep_parse_result->config_size);
|
|
|
|
|
|
|
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*extra = (void *) pconf;
|
|
|
|
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
/*
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
* We need not explicitly clean up syncrep_parse_result. It, and any
|
|
|
|
* other cruft generated during parsing, will be freed when the
|
|
|
|
* current memory context is deleted. (This code is generally run in
|
|
|
|
* a short-lived context used for config file processing, so that will
|
|
|
|
* not be very long.)
|
Support multiple synchronous standby servers.
Previously synchronous replication offered only the ability to confirm
that all changes made by a transaction had been transferred to at most
one synchronous standby server.
This commit extends synchronous replication so that it supports multiple
synchronous standby servers. It enables users to consider one or more
standby servers as synchronous, and increase the level of transaction
durability by ensuring that transaction commits wait for replies from
all of those synchronous standbys.
Multiple synchronous standby servers are configured in
synchronous_standby_names which is extended to support new syntax of
'num_sync ( standby_name [ , ... ] )', where num_sync specifies
the number of synchronous standbys that transaction commits need to
wait for replies from and standby_name is the name of a standby
server.
The syntax of 'standby_name [ , ... ]' which was used in 9.5 or before
is also still supported. It's the same as new syntax with num_sync=1.
This commit doesn't include "quorum commit" feature which was discussed
in pgsql-hackers. Synchronous standbys are chosen based on their priorities.
synchronous_standby_names determines the priority of each standby for
being chosen as a synchronous standby. The standbys whose names appear
earlier in the list are given higher priority and will be considered as
synchronous. Other standby servers appearing later in this list
represent potential synchronous standbys.
The regression test for multiple synchronous standbys is not included
in this commit. It should come later.
Authors: Sawada Masahiko, Beena Emerson, Michael Paquier, Fujii Masao
Reviewed-By: Kyotaro Horiguchi, Amit Kapila, Robert Haas, Simon Riggs,
Amit Langote, Thomas Munro, Sameer Thakur, Suraj Kharage, Abhijit Menon-Sen,
Rajeev Rastogi
Many thanks to the various individuals who were involved in
discussing and developing this feature.
2016-04-06 10:18:25 +02:00
|
|
|
*/
|
|
|
|
}
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
else
|
|
|
|
*extra = NULL;
|
2011-03-07 00:39:14 +01:00
|
|
|
|
2011-04-07 06:11:01 +02:00
|
|
|
return true;
|
2011-03-07 00:39:14 +01:00
|
|
|
}
|
2012-01-24 21:22:37 +01:00
|
|
|
|
Clean up parsing of synchronous_standby_names GUC variable.
Commit 989be0810dffd08b added a flex/bison lexer/parser to interpret
synchronous_standby_names. It was done in a pretty crufty way, though,
making assorted end-use sites responsible for calling the parser at the
right times. That was not only vulnerable to errors of omission, but made
it possible that lexer/parser errors occur at very undesirable times,
and created memory leakages even if there was no error.
Instead, perform the parsing once during check_synchronous_standby_names
and let guc.c manage the resulting data. To do that, we have to flatten
the parsed representation into a single hunk of malloc'd memory, but that
is not very hard.
While at it, work a little harder on making useful error reports for
parsing problems; the previous code felt that "synchronous_standby_names
parser returned 1" was an appropriate user-facing error message. (To
be fair, it did also log a syntax error message, but separately from the
GUC problem report, which is at best confusing.) It had some outright
bugs in the face of invalid input, too.
I (tgl) also concluded that we need to restrict unquoted names in
synchronous_standby_names to be just SQL identifiers. The previous coding
would accept darn near anything, which (1) makes the quoting convention
both nearly-unnecessary and formally ambiguous, (2) makes it very hard to
understand what is a syntax error and what is a creative interpretation of
the input as a standby name, and (3) makes it impossible to further extend
the syntax in future without a compatibility break. I presume that we're
intending future extensions of the syntax, else this parsing infrastructure
is massive overkill, so (3) is an important objection. Since we've taken
a compatibility hit for non-identifier names with this change anyway, we
might as well lock things down now and insist that users use double quotes
for standby names that aren't identifiers.
Kyotaro Horiguchi and Tom Lane
2016-04-27 23:55:19 +02:00
|
|
|
void
|
|
|
|
assign_synchronous_standby_names(const char *newval, void *extra)
|
|
|
|
{
|
|
|
|
SyncRepConfig = (SyncRepConfigData *) extra;
|
|
|
|
}
|
|
|
|
|
2012-01-24 21:22:37 +01:00
|
|
|
void
|
|
|
|
assign_synchronous_commit(int newval, void *extra)
|
|
|
|
{
|
|
|
|
switch (newval)
|
|
|
|
{
|
|
|
|
case SYNCHRONOUS_COMMIT_REMOTE_WRITE:
|
|
|
|
SyncRepWaitMode = SYNC_REP_WAIT_WRITE;
|
|
|
|
break;
|
|
|
|
case SYNCHRONOUS_COMMIT_REMOTE_FLUSH:
|
|
|
|
SyncRepWaitMode = SYNC_REP_WAIT_FLUSH;
|
|
|
|
break;
|
2016-03-30 03:16:12 +02:00
|
|
|
case SYNCHRONOUS_COMMIT_REMOTE_APPLY:
|
|
|
|
SyncRepWaitMode = SYNC_REP_WAIT_APPLY;
|
|
|
|
break;
|
2012-01-24 21:22:37 +01:00
|
|
|
default:
|
|
|
|
SyncRepWaitMode = SYNC_REP_NO_WAIT;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|