2011-09-12 20:24:29 +02:00
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/*-------------------------------------------------------------------------
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*
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* walsender_private.h
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* Private definitions from replication/walsender.c.
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*
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2012-01-02 00:01:58 +01:00
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* Portions Copyright (c) 2010-2012, PostgreSQL Global Development Group
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2011-09-12 20:24:29 +02:00
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*
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* src/include/replication/walsender_private.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef _WALSENDER_PRIVATE_H
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#define _WALSENDER_PRIVATE_H
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#include "access/xlog.h"
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#include "nodes/nodes.h"
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2012-01-24 21:22:37 +01:00
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#include "replication/syncrep.h"
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2011-09-12 20:24:29 +02:00
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#include "storage/latch.h"
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#include "storage/shmem.h"
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#include "storage/spin.h"
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typedef enum WalSndState
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{
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WALSNDSTATE_STARTUP = 0,
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WALSNDSTATE_BACKUP,
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WALSNDSTATE_CATCHUP,
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WALSNDSTATE_STREAMING
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} WalSndState;
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/*
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* Each walsender has a WalSnd struct in shared memory.
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*/
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typedef struct WalSnd
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{
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pid_t pid; /* this walsender's process id, or 0 */
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WalSndState state; /* this walsender's state */
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XLogRecPtr sentPtr; /* WAL has been sent up to this point */
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2012-06-10 21:20:04 +02:00
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bool needreload; /* does currently-open file need to be
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* reloaded? */
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2011-09-12 20:24:29 +02:00
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/*
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* The xlog locations that have been written, flushed, and applied by
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* standby-side. These may be invalid if the standby-side has not offered
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* values yet.
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*/
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XLogRecPtr write;
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XLogRecPtr flush;
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XLogRecPtr apply;
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/* Protects shared variables shown above. */
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slock_t mutex;
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/*
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* Latch used by backends to wake up this walsender when it has work to
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* do.
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*/
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Latch latch;
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/*
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* The priority order of the standby managed by this WALSender, as listed
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* in synchronous_standby_names, or 0 if not-listed. Protected by
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* SyncRepLock.
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*/
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int sync_standby_priority;
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} WalSnd;
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extern WalSnd *MyWalSnd;
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/* There is one WalSndCtl struct for the whole database cluster */
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typedef struct
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{
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/*
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2012-01-24 21:22:37 +01:00
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* Synchronous replication queue with one queue per request type.
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* Protected by SyncRepLock.
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2011-09-12 20:24:29 +02:00
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*/
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2012-01-24 21:22:37 +01:00
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SHM_QUEUE SyncRepQueue[NUM_SYNC_REP_WAIT_MODE];
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2011-09-12 20:24:29 +02:00
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/*
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* Current location of the head of the queue. All waiters should have a
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* waitLSN that follows this value. Protected by SyncRepLock.
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*/
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2012-01-24 21:22:37 +01:00
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XLogRecPtr lsn[NUM_SYNC_REP_WAIT_MODE];
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2011-09-12 20:24:29 +02:00
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/*
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* Are any sync standbys defined? Waiting backends can't reload the
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2012-01-30 15:34:25 +01:00
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* config file safely, so checkpointer updates this value as needed.
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2011-09-12 20:24:29 +02:00
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* Protected by SyncRepLock.
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*/
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bool sync_standbys_defined;
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WalSnd walsnds[1]; /* VARIABLE LENGTH ARRAY */
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} WalSndCtlData;
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extern WalSndCtlData *WalSndCtl;
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extern void WalSndSetState(WalSndState state);
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Allow a streaming replication standby to follow a timeline switch.
Before this patch, streaming replication would refuse to start replicating
if the timeline in the primary doesn't exactly match the standby. The
situation where it doesn't match is when you have a master, and two
standbys, and you promote one of the standbys to become new master.
Promoting bumps up the timeline ID, and after that bump, the other standby
would refuse to continue.
There's significantly more timeline related logic in streaming replication
now. First of all, when a standby connects to primary, it will ask the
primary for any timeline history files that are missing from the standby.
The missing files are sent using a new replication command TIMELINE_HISTORY,
and stored in standby's pg_xlog directory. Using the timeline history files,
the standby can follow the latest timeline present in the primary
(recovery_target_timeline='latest'), just as it can follow new timelines
appearing in an archive directory.
START_REPLICATION now takes a TIMELINE parameter, to specify exactly which
timeline to stream WAL from. This allows the standby to request the primary
to send over WAL that precedes the promotion. The replication protocol is
changed slightly (in a backwards-compatible way although there's little hope
of streaming replication working across major versions anyway), to allow
replication to stop when the end of timeline reached, putting the walsender
back into accepting a replication command.
Many thanks to Amit Kapila for testing and reviewing various versions of
this patch.
2012-12-13 18:00:00 +01:00
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extern void XLogRead(char *buf, TimeLineID tli, XLogRecPtr startptr, Size count);
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2011-09-12 20:24:29 +02:00
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/*
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* Internal functions for parsing the replication grammar, in repl_gram.y and
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* repl_scanner.l
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*/
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extern int replication_yyparse(void);
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extern int replication_yylex(void);
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extern void replication_yyerror(const char *str);
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extern void replication_scanner_init(const char *query_string);
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extern void replication_scanner_finish(void);
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extern Node *replication_parse_result;
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#endif /* _WALSENDER_PRIVATE_H */
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