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postgresql/src/include/storage/standby.h

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Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
/*-------------------------------------------------------------------------
*
* standby.h
* Definitions for hot standby mode.
*
*
Update copyright for 2022 Backpatch-through: 10
2022-01-08 01:04:57 +01:00
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
* Portions Copyright (c) 1994, Regents of the University of California
*
Remove cvs keywords from all files.
2010-09-20 22:08:53 +02:00
* src/include/storage/standby.h
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
*
*-------------------------------------------------------------------------
*/
#ifndef STANDBY_H
#define STANDBY_H
Make storage/standby.h compile standalone again. This file has failed headerscheck/cpluspluscheck verification since commit 0650ff230, as a result of referencing typedef TimestampTz without including the appropriate header.
2021-01-25 00:08:55 +01:00
#include "datatype/timestamp.h"
Rework wait for AccessExclusiveLocks on Hot Standby Earlier version committed in 9.0 caused spurious waits in some cases. New infrastructure for lock waits in 9.3 used to correct and improve this. Jeff Janes based upon a proposal by Simon Riggs, who also reviewed Additional review comments from Amit Kapila
2016-03-10 20:26:24 +01:00
#include "storage/lock.h"
Re-enable max_standby_delay = -1 using deadlock detection on startup process. If startup waits on a buffer pin we send a request to all backends to cancel themselves if they are holding the buffer pin required and they are also waiting on a lock. If not, startup waits until max_standby_delay before cancelling any backend waiting for the requested buffer pin.
2010-02-13 02:32:20 +01:00
#include "storage/procsignal.h"
Clean up the #include mess a little. walsender.h should depend on xlog.h, not vice versa. (Actually, the inclusion was circular until a couple hours ago, which was even sillier; but Bruce broke it in the expedient rather than logically correct direction.) Because of that poor decision, plus blind application of pgrminclude, we had a situation where half the system was depending on xlog.h to include such unrelated stuff as array.h and guc.h. Clean up the header inclusion, and manually revert a lot of what pgrminclude had done so things build again. This episode reinforces my feeling that pgrminclude should not be run without adult supervision. Inclusion changes in header files in particular need to be reviewed with great care. More generally, it'd be good if we had a clearer notion of module layering to dictate which headers can sanely include which others ... but that's a big task for another day.
2011-09-04 07:13:16 +02:00
#include "storage/relfilenode.h"
Make the order of the header file includes consistent. Similar to commits 14aec03502, 7e735035f2 and dddf4cdc33, this commit makes the order of header file inclusion consistent in more places. Author: Vignesh C Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
2019-11-25 03:38:57 +01:00
#include "storage/standbydefs.h"
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
Replace max_standby_delay with two parameters, max_standby_archive_delay and max_standby_streaming_delay, and revise the implementation to avoid assuming that timestamps found in WAL records can meaningfully be compared to clock time on the standby server. Instead, the delay limits are compared to the elapsed time since we last obtained a new WAL segment from archive or since we were last "caught up" to WAL data arriving via streaming replication. This avoids problems with clock skew between primary and standby, as well as other corner cases that the original coding would misbehave in, such as the primary server having significant idle time between transactions. Per my complaint some time ago and considerable ensuing discussion. Do some desultory editing on the hot standby documentation, too.
2010-07-03 22:43:58 +02:00
/* User-settable GUC parameters */
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
extern int vacuum_defer_cleanup_age;
Replace max_standby_delay with two parameters, max_standby_archive_delay and max_standby_streaming_delay, and revise the implementation to avoid assuming that timestamps found in WAL records can meaningfully be compared to clock time on the standby server. Instead, the delay limits are compared to the elapsed time since we last obtained a new WAL segment from archive or since we were last "caught up" to WAL data arriving via streaming replication. This avoids problems with clock skew between primary and standby, as well as other corner cases that the original coding would misbehave in, such as the primary server having significant idle time between transactions. Per my complaint some time ago and considerable ensuing discussion. Do some desultory editing on the hot standby documentation, too.
2010-07-03 22:43:58 +02:00
extern int max_standby_archive_delay;
extern int max_standby_streaming_delay;
Add GUC to log long wait times on recovery conflicts. This commit adds GUC log_recovery_conflict_waits that controls whether a log message is produced when the startup process is waiting longer than deadlock_timeout for recovery conflicts. This is useful in determining if recovery conflicts prevent the recovery from applying WAL. Note that currently a log message is produced only when recovery conflict has not been resolved yet even after deadlock_timeout passes, i.e., only when the startup process is still waiting for recovery conflict even after deadlock_timeout. Author: Bertrand Drouvot, Masahiko Sawada Reviewed-by: Alvaro Herrera, Kyotaro Horiguchi, Fujii Masao Discussion: https://postgr.es/m/9a60178c-a853-1440-2cdc-c3af916cff59@amazon.com
2021-01-07 16:47:03 +01:00
extern bool log_recovery_conflict_waits;
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
In HS, Startup process sets SIGALRM when waiting for buffer pin. If woken by alarm we send SIGUSR1 to all backends requesting that they check to see if they are blocking Startup process. If so, they throw ERROR/FATAL as for other conflict resolutions. Deadlock stop gap removed. max_standby_delay = -1 option removed to prevent deadlock.
2010-01-23 17:37:12 +01:00
extern void InitRecoveryTransactionEnvironment(void);
extern void ShutdownRecoveryTransactionEnvironment(void);
Filter recovery conflicts based upon dboid from relfilenode of WAL records for heap and btree. Minor change, mostly API changes to pass through the required values. This is a simple change though also provides the refactoring required for further enhancements to conflict processing using the relOid. Changes only have effect during Hot Standby.
2010-01-29 18:10:05 +01:00
extern void ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid,
RelFileNode node);
Use full 64-bit XIDs in deleted nbtree pages. Otherwise we risk "leaking" deleted pages by making them non-recyclable indefinitely. Commit 6655a729 did the same thing for deleted pages in GiST indexes. That work was used as a starting point here. Stop storing an XID indicating the oldest bpto.xact across all deleted though unrecycled pages in nbtree metapages. There is no longer any reason to care about that condition/the oldest XID. It only ever made sense when wraparound was something _bt_vacuum_needs_cleanup() had to consider. The btm_oldest_btpo_xact metapage field has been repurposed and renamed. It is now btm_last_cleanup_num_delpages, which is used to remember how many non-recycled deleted pages remain from the last VACUUM (in practice its value is usually the precise number of pages that were _newly deleted_ during the specific VACUUM operation that last set the field). The general idea behind storing btm_last_cleanup_num_delpages is to use it to give _some_ consideration to non-recycled deleted pages inside _bt_vacuum_needs_cleanup() -- though never too much. We only really need to avoid leaving a truly excessive number of deleted pages in an unrecycled state forever. We only do this to cover certain narrow cases where no other factor makes VACUUM do a full scan, and yet the index continues to grow (and so actually misses out on recycling existing deleted pages). These metapage changes result in a clear user-visible benefit: We no longer trigger full index scans during VACUUM operations solely due to the presence of only 1 or 2 known deleted (though unrecycled) blocks from a very large index. All that matters now is keeping the costs and benefits in balance over time. Fix an issue that has been around since commit 857f9c36, which added the "skip full scan of index" mechanism (i.e. the _bt_vacuum_needs_cleanup() logic). The accuracy of btm_last_cleanup_num_heap_tuples accidentally hinged upon _when_ the source value gets stored. We now always store btm_last_cleanup_num_heap_tuples in btvacuumcleanup(). This fixes the issue because IndexVacuumInfo.num_heap_tuples (the source field) is expected to accurately indicate the state of the table _after_ the VACUUM completes inside btvacuumcleanup(). A backpatchable fix cannot easily be extracted from this commit. A targeted fix for the issue will follow in a later commit, though that won't happen today. I (pgeoghegan) have chosen to remove any mention of deleted pages in the documentation of the vacuum_cleanup_index_scale_factor GUC/param, since the presence of deleted (though unrecycled) pages is no longer of much concern to users. The vacuum_cleanup_index_scale_factor description in the docs now seems rather unclear in any case, and it should probably be rewritten in the near future. Perhaps some passing mention of page deletion will be added back at the same time. Bump XLOG_PAGE_MAGIC due to nbtree WAL records using full XIDs now. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAH2-WznpdHvujGUwYZ8sihX=d5u-tRYhi-F4wnV2uN2zHpMUXw@mail.gmail.com
2021-02-25 03:41:34 +01:00
extern void ResolveRecoveryConflictWithSnapshotFullXid(FullTransactionId latestRemovedFullXid,
RelFileNode node);
First part of refactoring of code for ResolveRecoveryConflict. Purposes of this are to centralise the conflict code to allow further change, as well as to allow passing through the full reason for the conflict through to the conflicting backends. Backend state alters how we can handle different types of conflict so this is now required. As originally suggested by Heikki, no longer optional.
2010-01-14 12:08:02 +01:00
extern void ResolveRecoveryConflictWithTablespace(Oid tsid);
extern void ResolveRecoveryConflictWithDatabase(Oid dbid);
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
Add GUC to log long wait times on recovery conflicts. This commit adds GUC log_recovery_conflict_waits that controls whether a log message is produced when the startup process is waiting longer than deadlock_timeout for recovery conflicts. This is useful in determining if recovery conflicts prevent the recovery from applying WAL. Note that currently a log message is produced only when recovery conflict has not been resolved yet even after deadlock_timeout passes, i.e., only when the startup process is still waiting for recovery conflict even after deadlock_timeout. Author: Bertrand Drouvot, Masahiko Sawada Reviewed-by: Alvaro Herrera, Kyotaro Horiguchi, Fujii Masao Discussion: https://postgr.es/m/9a60178c-a853-1440-2cdc-c3af916cff59@amazon.com
2021-01-07 16:47:03 +01:00
extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag, bool logging_conflict);
In HS, Startup process sets SIGALRM when waiting for buffer pin. If woken by alarm we send SIGUSR1 to all backends requesting that they check to see if they are blocking Startup process. If so, they throw ERROR/FATAL as for other conflict resolutions. Deadlock stop gap removed. max_standby_delay = -1 option removed to prevent deadlock.
2010-01-23 17:37:12 +01:00
extern void ResolveRecoveryConflictWithBufferPin(void);
Move CheckRecoveryConflictDeadlock() call to a safer place. This kluge was inserted in a spot apparently chosen at random: the lock manager's state is not yet fully set up for the wait, and in particular LockWaitCancel hasn't been armed by setting lockAwaited, so the ProcLock will not get cleaned up if the ereport is thrown. This seems to not cause any observable problem in trivial test cases, because LockReleaseAll will silently clean up the debris; but I was able to cause failures with tests involving subtransactions. Fixes breakage induced by commit c85c941470efc44494fd7a5f426ee85fc65c268c. Back-patch to all affected branches.
2011-08-02 21:16:29 +02:00
extern void CheckRecoveryConflictDeadlock(void);
Introduce timeout handling framework Management of timeouts was getting a little cumbersome; what we originally had was more than enough back when we were only concerned about deadlocks and query cancel; however, when we added timeouts for standby processes, the code got considerably messier. Since there are plans to add more complex timeouts, this seems a good time to introduce a central timeout handling module. External modules register their timeout handlers during process initialization, and later enable and disable them as they see fit using a simple API; timeout.c is in charge of keeping track of which timeouts are in effect at any time, installing a common SIGALRM signal handler, and calling setitimer() as appropriate to ensure timely firing of external handlers. timeout.c additionally supports pluggable modules to add their own timeouts, though this capability isn't exercised anywhere yet. Additionally, as of this commit, walsender processes are aware of timeouts; we had a preexisting bug there that made those ignore SIGALRM, thus being subject to unhandled deadlocks, particularly during the authentication phase. This has already been fixed in back branches in commit 0bf8eb2a, which see for more details. Main author: Zoltán Böszörményi Some review and cleanup by Álvaro Herrera Extensive reworking by Tom Lane
2012-07-17 00:43:21 +02:00
extern void StandbyDeadLockHandler(void);
extern void StandbyTimeoutHandler(void);
Rework wait for AccessExclusiveLocks on Hot Standby Earlier version committed in 9.0 caused spurious waits in some cases. New infrastructure for lock waits in 9.3 used to correct and improve this. Jeff Janes based upon a proposal by Simon Riggs, who also reviewed Additional review comments from Amit Kapila
2016-03-10 20:26:24 +01:00
extern void StandbyLockTimeoutHandler(void);
Add GUC to log long wait times on recovery conflicts. This commit adds GUC log_recovery_conflict_waits that controls whether a log message is produced when the startup process is waiting longer than deadlock_timeout for recovery conflicts. This is useful in determining if recovery conflicts prevent the recovery from applying WAL. Note that currently a log message is produced only when recovery conflict has not been resolved yet even after deadlock_timeout passes, i.e., only when the startup process is still waiting for recovery conflict even after deadlock_timeout. Author: Bertrand Drouvot, Masahiko Sawada Reviewed-by: Alvaro Herrera, Kyotaro Horiguchi, Fujii Masao Discussion: https://postgr.es/m/9a60178c-a853-1440-2cdc-c3af916cff59@amazon.com
2021-01-07 16:47:03 +01:00
extern void LogRecoveryConflict(ProcSignalReason reason, TimestampTz wait_start,
Log long wait time on recovery conflict when it's resolved. This is a follow-up of the work done in commit 0650ff2303. This commit extends log_recovery_conflict_waits so that a log message is produced also when recovery conflict has already been resolved after deadlock_timeout passes, i.e., when the startup process finishes waiting for recovery conflict after deadlock_timeout. This is useful in investigating how long recovery conflicts prevented the recovery from applying WAL. Author: Fujii Masao Reviewed-by: Kyotaro Horiguchi, Bertrand Drouvot Discussion: https://postgr.es/m/9a60178c-a853-1440-2cdc-c3af916cff59@amazon.com
2021-01-13 14:59:17 +01:00
TimestampTz cur_ts, VirtualTransactionId *wait_list,
bool still_waiting);
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
/*
* Standby Rmgr (RM_STANDBY_ID)
*
* Standby recovery manager exists to perform actions that are required
* to make hot standby work. That includes logging AccessExclusiveLocks taken
* by transactions and running-xacts snapshots.
*/
extern void StandbyAcquireAccessExclusiveLock(TransactionId xid, Oid dbOid, Oid relOid);
extern void StandbyReleaseLockTree(TransactionId xid,
int nsubxids, TransactionId *subxids);
extern void StandbyReleaseAllLocks(void);
Remove AELs from subxids correctly on standby Issues relate only to subtransactions that hold AccessExclusiveLocks when replayed on standby. Prior to PG10, aborting subtransactions that held an AccessExclusiveLock failed to release the lock until top level commit or abort. 49bff5300d527 fixed that. However, 49bff5300d527 also introduced a similar bug where subtransaction commit would fail to release an AccessExclusiveLock, leaving the lock to be removed sometimes early and sometimes late. This commit fixes that bug also. Backpatch to PG10 needed. Tested by observation. Note need for multi-node isolationtester to improve test coverage for this and other HS cases. Reported-by: Simon Riggs Author: Simon Riggs
2018-06-16 15:03:29 +02:00
extern void StandbyReleaseOldLocks(TransactionId oldxid);
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
#define MinSizeOfXactRunningXacts offsetof(xl_running_xacts, xids)
/*
* Declarations for GetRunningTransactionData(). Similar to Snapshots, but
* not quite. This has nothing at all to do with visibility on this server,
Replace max_standby_delay with two parameters, max_standby_archive_delay and max_standby_streaming_delay, and revise the implementation to avoid assuming that timestamps found in WAL records can meaningfully be compared to clock time on the standby server. Instead, the delay limits are compared to the elapsed time since we last obtained a new WAL segment from archive or since we were last "caught up" to WAL data arriving via streaming replication. This avoids problems with clock skew between primary and standby, as well as other corner cases that the original coding would misbehave in, such as the primary server having significant idle time between transactions. Per my complaint some time ago and considerable ensuing discussion. Do some desultory editing on the hot standby documentation, too.
2010-07-03 22:43:58 +02:00
* so this is completely separate from snapmgr.c and snapmgr.h.
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
* This data is important for creating the initial snapshot state on a
* standby server. We need lots more information than a normal snapshot,
* hence we use a specific data structure for our needs. This data
* is written to WAL as a separate record immediately after each
* checkpoint. That means that wherever we start a standby from we will
* almost immediately see the data we need to begin executing queries.
*/
typedef struct RunningTransactionsData
{
int xcnt; /* # of xact ids in xids[] */
Rearrange storage of data in xl_running_xacts. Previously we stored all xids mixed together. Now we store top-level xids first, followed by all subxids. Also skip logging any subxids if the snapshot is suboverflowed, since there are potentially large numbers of them and they are not useful in that case anyway. Has value in the envisaged design for decoding of WAL. No planned effect on Hot Standby. Andres Freund, reviewed by me
2012-12-02 20:39:37 +01:00
int subxcnt; /* # of subxact ids in xids[] */
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
bool subxid_overflow; /* snapshot overflowed, subxids missing */
Rename VariableCacheData.nextFullXid to nextXid. Including Full in variable names duplicates the type information and leads to overly long names. As FullTransactionId cannot accidentally be casted to TransactionId that does not seem necessary. Author: Andres Freund Discussion: https://postgr.es/m/20200724011143.jccsyvsvymuiqfxu@alap3.anarazel.de
2020-08-11 20:25:23 +02:00
TransactionId nextXid; /* xid from ShmemVariableCache->nextXid */
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
TransactionId oldestRunningXid; /* *not* oldestXmin */
Cleanup initialization of Hot Standby. Clarify working with reanalysis of requirements and documentation on LogStandbySnapshot(). Fixes two minor bugs reported by Tom Lane that would lead to an incorrect snapshot after transaction wraparound. Also fix two other problems discovered that would give incorrect snapshots in certain cases. ProcArrayApplyRecoveryInfo() substantially rewritten. Some minor refactoring of xact_redo_apply() and ExpireTreeKnownAssignedTransactionIds().
2010-05-13 13:15:38 +02:00
TransactionId latestCompletedXid; /* so we can set xmax */
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
TransactionId *xids; /* array of (sub)xids still running */
} RunningTransactionsData;
typedef RunningTransactionsData *RunningTransactions;
extern void LogAccessExclusiveLock(Oid dbOid, Oid relOid);
Move call to GetTopTransactionId() earlier in LockAcquire(), removing an infrequently occurring race condition in Hot Standby. An xid must be assigned before a lock appears in shared memory, rather than immediately after, else GetRunningTransactionLocks() may see InvalidTransactionId, causing assertion failures during lock processing on standby. Bug report and diagnosis by Fujii Masao, fix by me.
2010-11-29 02:08:02 +01:00
extern void LogAccessExclusiveLockPrepare(void);
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
Logging running transactions every 15 seconds. Previously, we did this just once per checkpoint, but that could make Hot Standby take a long time to initialize. To avoid busying an otherwise-idle system, we don't do this if no WAL has been written since we did it last. Andres Freund
2014-01-15 18:41:20 +01:00
extern XLogRecPtr LogStandbySnapshot(void);
Emit invalidations to standby for transactions without xid. So far, when a transaction with pending invalidations, but without an assigned xid, committed, we simply ignored those invalidation messages. That's problematic, because those are actually sent for a reason. Known symptoms of this include that existing sessions on a hot-standby replica sometimes fail to notice new concurrently built indexes and visibility map updates. The solution is to WAL log such invalidations in transactions without an xid. We considered to alternatively force-assign an xid, but that'd be problematic for vacuum, which might be run in systems with few xids. Important: This adds a new WAL record, but as the patch has to be back-patched, we can't bump the WAL page magic. This means that standbys have to be updated before primaries; otherwise "PANIC: standby_redo: unknown op code 32" errors can be encountered. XXX: Reported-By: Васильев Дмитрий, Masahiko Sawada Discussion: CAB-SwXY6oH=9twBkXJtgR4UC1NqT-vpYAtxCseME62ADwyK5OA@mail.gmail.com CAD21AoDpZ6Xjg=gFrGPnSn4oTRRcwK1EBrWCq9OqOHuAcMMC=w@mail.gmail.com
2016-04-24 04:18:00 +02:00
extern void LogStandbyInvalidations(int nmsgs, SharedInvalidationMessage *msgs,
bool relcacheInitFileInval);
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
#endif /* STANDBY_H */