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postgresql/src/include/replication/walsender_private.h

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Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
/*-------------------------------------------------------------------------
*
* walsender_private.h
* Private definitions from replication/walsender.c.
*
Update copyright via script for 2017
2017-01-03 19:48:53 +01:00
* Portions Copyright (c) 2010-2017, PostgreSQL Global Development Group
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
*
* src/include/replication/walsender_private.h
*
*-------------------------------------------------------------------------
*/
#ifndef _WALSENDER_PRIVATE_H
#define _WALSENDER_PRIVATE_H
#include "access/xlog.h"
#include "nodes/nodes.h"
Add new replication mode synchronous_commit = 'write'. Replication occurs only to memory on standby, not to disk, so provides additional performance if user wishes to reduce durability level slightly. Adds concept of multiple independent sync rep queues. Fujii Masao and Simon Riggs
2012-01-24 21:22:37 +01:00
#include "replication/syncrep.h"
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
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#include "storage/latch.h"
#include "storage/shmem.h"
#include "storage/spin.h"
typedef enum WalSndState
{
WALSNDSTATE_STARTUP = 0,
WALSNDSTATE_BACKUP,
WALSNDSTATE_CATCHUP,
Prevent possibility of panics during shutdown checkpoint. When the checkpointer writes the shutdown checkpoint, it checks afterwards whether any WAL has been written since it started and throws a PANIC if so. At that point, only walsenders are still active, so one might think this could not happen, but walsenders can also generate WAL, for instance in BASE_BACKUP and logical decoding related commands (e.g. via hint bits). So they can trigger this panic if such a command is run while the shutdown checkpoint is being written. To fix this, divide the walsender shutdown into two phases. First, checkpointer, itself triggered by postmaster, sends a PROCSIG_WALSND_INIT_STOPPING signal to all walsenders. If the backend is idle or runs an SQL query this causes the backend to shutdown, if logical replication is in progress all existing WAL records are processed followed by a shutdown. Otherwise this causes the walsender to switch to the "stopping" state. In this state, the walsender will reject any further replication commands. The checkpointer begins the shutdown checkpoint once all walsenders are confirmed as stopping. When the shutdown checkpoint finishes, the postmaster sends us SIGUSR2. This instructs walsender to send any outstanding WAL, including the shutdown checkpoint record, wait for it to be replicated to the standby, and then exit. Author: Andres Freund, based on an earlier patch by Michael Paquier Reported-By: Fujii Masao, Andres Freund Reviewed-By: Michael Paquier Discussion: https://postgr.es/m/20170602002912.tqlwn4gymzlxpvs2@alap3.anarazel.de Backpatch: 9.4, where logical decoding was introduced
2017-06-06 03:53:41 +02:00
WALSNDSTATE_STREAMING,
WALSNDSTATE_STOPPING
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
} WalSndState;
/*
* Each walsender has a WalSnd struct in shared memory.
*/
typedef struct WalSnd
{
pid_t pid; /* this walsender's process id, or 0 */
WalSndState state; /* this walsender's state */
XLogRecPtr sentPtr; /* WAL has been sent up to this point */
Run pgindent on 9.2 source tree in preparation for first 9.3 commit-fest.
2012-06-10 21:20:04 +02:00
bool needreload; /* does currently-open file need to be
* reloaded? */
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
/*
* The xlog locations that have been written, flushed, and applied by
* standby-side. These may be invalid if the standby-side has not offered
* values yet.
*/
XLogRecPtr write;
XLogRecPtr flush;
XLogRecPtr apply;
Replication lag tracking for walsenders Adds write_lag, flush_lag and replay_lag cols to pg_stat_replication. Implements a lag tracker module that reports the lag times based upon measurements of the time taken for recent WAL to be written, flushed and replayed and for the sender to hear about it. These times represent the commit lag that was (or would have been) introduced by each synchronous commit level, if the remote server was configured as a synchronous standby. For an asynchronous standby, the replay_lag column approximates the delay before recent transactions became visible to queries. If the standby server has entirely caught up with the sending server and there is no more WAL activity, the most recently measured lag times will continue to be displayed for a short time and then show NULL. Physical replication lag tracking is automatic. Logical replication tracking is possible but is the responsibility of the logical decoding plugin. Tracking is a private module operating within each walsender individually, with values reported to shared memory. Module not used outside of walsender. Design and code is good enough now to commit - kudos to the author. In many ways a difficult topic, with important and subtle behaviour so this shoudl be expected to generate discussion and multiple open items: Test now! Author: Thomas Munro, following designs by Fujii Masao and Simon Riggs Review: Simon Riggs, Ian Barwick and Craig Ringer
2017-03-23 15:05:28 +01:00
/* Measured lag times, or -1 for unknown/none. */
TimeOffset writeLag;
TimeOffset flushLag;
TimeOffset applyLag;
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
/* Protects shared variables shown above. */
slock_t mutex;
/*
Replace walsender's latch with the general shared latch. Relying on the normal shared latch simplifies interrupt/signal handling because we can rely on all signal handlers setting the proc latch. That in turn allows us to avoid the use of ImmediateInterruptOK, which arguably isn't correct because WaitLatchOrSocket isn't declared to be immediately interruptible. Also change sections that wait on the walsender's latch to notice interrupts quicker/more reliably and make them more consistent with each other. This is part of a larger "get rid of ImmediateInterruptOK" series. Discussion: 20150115020335.GZ5245@awork2.anarazel.de
2015-01-17 13:00:42 +01:00
* Pointer to the walsender's latch. Used by backends to wake up this
* walsender when it has work to do. NULL if the walsender isn't active.
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
*/
Use FLEXIBLE_ARRAY_MEMBER in a bunch more places. Replace some bogus "x[1]" declarations with "x[FLEXIBLE_ARRAY_MEMBER]". Aside from being more self-documenting, this should help prevent bogus warnings from static code analyzers and perhaps compiler misoptimizations. This patch is just a down payment on eliminating the whole problem, but it gets rid of a lot of easy-to-fix cases. Note that the main problem with doing this is that one must no longer rely on computing sizeof(the containing struct), since the result would be compiler-dependent. Instead use offsetof(struct, lastfield). Autoconf also warns against spelling that offsetof(struct, lastfield[0]). Michael Paquier, review and additional fixes by me.
2015-02-20 06:11:42 +01:00
Latch *latch;
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
/*
* The priority order of the standby managed by this WALSender, as listed
* in synchronous_standby_names, or 0 if not-listed. Protected by
* SyncRepLock.
*/
int sync_standby_priority;
} WalSnd;
extern WalSnd *MyWalSnd;
/* There is one WalSndCtl struct for the whole database cluster */
typedef struct
{
/*
Add new replication mode synchronous_commit = 'write'. Replication occurs only to memory on standby, not to disk, so provides additional performance if user wishes to reduce durability level slightly. Adds concept of multiple independent sync rep queues. Fujii Masao and Simon Riggs
2012-01-24 21:22:37 +01:00
* Synchronous replication queue with one queue per request type.
* Protected by SyncRepLock.
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
*/
Add new replication mode synchronous_commit = 'write'. Replication occurs only to memory on standby, not to disk, so provides additional performance if user wishes to reduce durability level slightly. Adds concept of multiple independent sync rep queues. Fujii Masao and Simon Riggs
2012-01-24 21:22:37 +01:00
SHM_QUEUE SyncRepQueue[NUM_SYNC_REP_WAIT_MODE];
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
/*
* Current location of the head of the queue. All waiters should have a
* waitLSN that follows this value. Protected by SyncRepLock.
*/
Add new replication mode synchronous_commit = 'write'. Replication occurs only to memory on standby, not to disk, so provides additional performance if user wishes to reduce durability level slightly. Adds concept of multiple independent sync rep queues. Fujii Masao and Simon Riggs
2012-01-24 21:22:37 +01:00
XLogRecPtr lsn[NUM_SYNC_REP_WAIT_MODE];
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
/*
* Are any sync standbys defined? Waiting backends can't reload the
Various minor comments changes from bgwriter to checkpointer.
2012-01-30 15:34:25 +01:00
* config file safely, so checkpointer updates this value as needed.
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
* Protected by SyncRepLock.
*/
bool sync_standbys_defined;
Use FLEXIBLE_ARRAY_MEMBER in a bunch more places. Replace some bogus "x[1]" declarations with "x[FLEXIBLE_ARRAY_MEMBER]". Aside from being more self-documenting, this should help prevent bogus warnings from static code analyzers and perhaps compiler misoptimizations. This patch is just a down payment on eliminating the whole problem, but it gets rid of a lot of easy-to-fix cases. Note that the main problem with doing this is that one must no longer rely on computing sizeof(the containing struct), since the result would be compiler-dependent. Instead use offsetof(struct, lastfield). Autoconf also warns against spelling that offsetof(struct, lastfield[0]). Michael Paquier, review and additional fixes by me.
2015-02-20 06:11:42 +01:00
WalSnd walsnds[FLEXIBLE_ARRAY_MEMBER];
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
} WalSndCtlData;
extern WalSndCtlData *WalSndCtl;
extern void WalSndSetState(WalSndState state);
/*
* Internal functions for parsing the replication grammar, in repl_gram.y and
* repl_scanner.l
*/
extern int replication_yyparse(void);
extern int replication_yylex(void);
Tweak __attribute__-wrapping macros for better pgindent results. This improves on commit bbfd7edae5aa5ad5553d3c7e102f2e450d4380d4 by making two simple changes: * pg_attribute_noreturn now takes parentheses, ie pg_attribute_noreturn(). Likewise pg_attribute_unused(), pg_attribute_packed(). This reduces pgindent's tendency to misformat declarations involving them. * attributes are now always attached to function declarations, not definitions. Previously some places were taking creative shortcuts, which were not merely candidates for bad misformatting by pgindent but often were outright wrong anyway. (It does little good to put a noreturn annotation where callers can't see it.) In any case, if we would like to believe that these macros can be used with non-gcc compilers, we should avoid gratuitous variance in usage patterns. I also went through and manually improved the formatting of a lot of declarations, and got rid of excessively repetitive (and now obsolete anyway) comments informing the reader what pg_attribute_printf is for.
2015-03-26 19:03:19 +01:00
extern void replication_yyerror(const char *str) pg_attribute_noreturn();
Split walsender.h in public/private headers This dramatically cuts short the number of headers the public one brings into whatever includes it.
2011-09-12 20:24:29 +02:00
extern void replication_scanner_init(const char *query_string);
extern void replication_scanner_finish(void);
extern Node *replication_parse_result;
#endif /* _WALSENDER_PRIVATE_H */