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Need to hold ControlFileLock while updating control file. Update

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minRecoveryPoint in control file when replaying a parameter change record,
to ensure that we don't allow hot standby on WAL generated without
wal_level='hot_standby' after a standby restart.
This commit is contained in:
Heikki Linnakangas
2010-05-03 11:17:52 +00:00
parent c0de88c415
commit ffe8c7c677
1 changed files with 18 additions and 1 deletions
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19
src/backend/access/transam/xlog.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.408 2010/05/02 02:10:33 tgl Exp $ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.409 2010/05/03 11:17:52 heikki Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -7920,11 +7920,28 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
/* Update our copy of the parameters in pg_control */ /* Update our copy of the parameters in pg_control */
memcpy(&xlrec, XLogRecGetData(record), sizeof(xl_parameter_change)); memcpy(&xlrec, XLogRecGetData(record), sizeof(xl_parameter_change));
LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
ControlFile->MaxConnections = xlrec.MaxConnections; ControlFile->MaxConnections = xlrec.MaxConnections;
ControlFile->max_prepared_xacts = xlrec.max_prepared_xacts; ControlFile->max_prepared_xacts = xlrec.max_prepared_xacts;
ControlFile->max_locks_per_xact = xlrec.max_locks_per_xact; ControlFile->max_locks_per_xact = xlrec.max_locks_per_xact;
ControlFile->wal_level = xlrec.wal_level; ControlFile->wal_level = xlrec.wal_level;
/*
* Update minRecoveryPoint to ensure that if recovery is aborted,
* we recover back up to this point before allowing hot standby
* again. This is particularly important if wal_level was set to
* 'archive' before, and is now 'hot_standby', to ensure you don't
* run queries against the WAL preceding the wal_level change.
* Same applies to decreasing max_* settings.
*/
minRecoveryPoint = ControlFile->minRecoveryPoint;
if ((minRecoveryPoint.xlogid != 0 || minRecoveryPoint.xrecoff != 0)
&& XLByteLT(minRecoveryPoint, lsn))
{
ControlFile->minRecoveryPoint = lsn;
}
UpdateControlFile(); UpdateControlFile();
LWLockRelease(ControlFileLock);
/* Check to see if any changes to max_connections give problems */ /* Check to see if any changes to max_connections give problems */
CheckRequiredParameterValues(); CheckRequiredParameterValues();