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/*-------------------------------------------------------------------------
*
* standby.h
* Definitions for hot standby mode.
*
*
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/storage/standby.h
*
*-------------------------------------------------------------------------
*/
#ifndef STANDBY_H
#define STANDBY_H
#include "access/xlog.h"
#include "storage/lock.h"
#include "storage/procsignal.h"
#include "storage/relfilenode.h"
/* User-settable GUC parameters */
extern int vacuum_defer_cleanup_age;
extern int max_standby_archive_delay;
extern int max_standby_streaming_delay;
extern void InitRecoveryTransactionEnvironment(void);
extern void ShutdownRecoveryTransactionEnvironment(void);
extern void ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid,
RelFileNode node);
extern void ResolveRecoveryConflictWithRemovedTransactionId(void);
extern void ResolveRecoveryConflictWithTablespace(Oid tsid);
extern void ResolveRecoveryConflictWithDatabase(Oid dbid);
extern void ResolveRecoveryConflictWithBufferPin(void);
extern void SendRecoveryConflictWithBufferPin(ProcSignalReason reason);
extern void CheckRecoveryConflictDeadlock(LWLockId partitionLock);
/*
* 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);
extern void StandbyReleaseOldLocks(TransactionId removeXid);
/*
* XLOG message types
*/
#define XLOG_STANDBY_LOCK 0x00
#define XLOG_RUNNING_XACTS 0x10
typedef struct xl_standby_locks
{
int nlocks; /* number of entries in locks array */
xl_standby_lock locks[1]; /* VARIABLE LENGTH ARRAY */
} xl_standby_locks;
/*
* When we write running xact data to WAL, we use this structure.
*/
typedef struct xl_running_xacts
{
int xcnt; /* # of xact ids in xids[] */
bool subxid_overflow; /* snapshot overflowed, subxids missing */
TransactionId nextXid; /* copy of ShmemVariableCache->nextXid */
TransactionId oldestRunningXid; /* *not* oldestXmin */
TransactionId latestCompletedXid; /* so we can set xmax */
TransactionId xids[1]; /* VARIABLE LENGTH ARRAY */
} xl_running_xacts;
#define MinSizeOfXactRunningXacts offsetof(xl_running_xacts, xids)
/* Recovery handlers for the Standby Rmgr (RM_STANDBY_ID) */
extern void standby_redo(XLogRecPtr lsn, XLogRecord *record);
extern void standby_desc(StringInfo buf, uint8 xl_info, char *rec);
/*
* Declarations for GetRunningTransactionData(). Similar to Snapshots, but
* not quite. This has nothing at all to do with visibility on this server,
* so this is completely separate from snapmgr.c and snapmgr.h.
* 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[] */
bool subxid_overflow; /* snapshot overflowed, subxids missing */
TransactionId nextXid; /* copy of ShmemVariableCache->nextXid */
TransactionId oldestRunningXid; /* *not* oldestXmin */
TransactionId latestCompletedXid; /* so we can set xmax */
TransactionId *xids; /* array of (sub)xids still running */
} RunningTransactionsData;
typedef RunningTransactionsData *RunningTransactions;
extern void LogAccessExclusiveLock(Oid dbOid, Oid relOid);
extern void LogStandbySnapshot(TransactionId *oldestActiveXid, TransactionId *nextXid);
#endif /* STANDBY_H */
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