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/*------------------------------------------------------------------------- * * standby.h * Definitions for hot standby mode. * * * Portions Copyright (c) 1996-2012, 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 ResolveRecoveryConflictWithTablespace(Oid tsid); extern void ResolveRecoveryConflictWithDatabase(Oid dbid); extern void ResolveRecoveryConflictWithBufferPin(void); extern void SendRecoveryConflictWithBufferPin(ProcSignalReason reason); extern void CheckRecoveryConflictDeadlock(void); /* * 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(int nxids, TransactionId *xids); /* * 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 LogAccessExclusiveLockPrepare(void); extern void LogStandbySnapshot(void); #endif /* STANDBY_H */