diff options
Diffstat (limited to 'src/backend/access/transam/multixact.c')
| -rw-r--r-- | src/backend/access/transam/multixact.c | 32 |
1 files changed, 9 insertions, 23 deletions
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index 46eca9c983..b272e9886b 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -42,7 +42,7 @@ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/multixact.c,v 1.32 2009/11/23 09:58:36 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/multixact.c,v 1.33 2009/12/19 01:32:33 sriggs Exp $ * *------------------------------------------------------------------------- */ @@ -59,6 +59,7 @@ #include "storage/backendid.h" #include "storage/lmgr.h" #include "storage/procarray.h" +#include "utils/builtins.h" #include "utils/memutils.h" @@ -220,7 +221,6 @@ static MultiXactId GetNewMultiXactId(int nxids, MultiXactOffset *offset); static MultiXactId mXactCacheGetBySet(int nxids, TransactionId *xids); static int mXactCacheGetById(MultiXactId multi, TransactionId **xids); static void mXactCachePut(MultiXactId multi, int nxids, TransactionId *xids); -static int xidComparator(const void *arg1, const void *arg2); #ifdef MULTIXACT_DEBUG static char *mxid_to_string(MultiXactId multi, int nxids, TransactionId *xids); @@ -1221,27 +1221,6 @@ mXactCachePut(MultiXactId multi, int nxids, TransactionId *xids) MXactCache = entry; } -/* - * xidComparator - * qsort comparison function for XIDs - * - * We don't need to use wraparound comparison for XIDs, and indeed must - * not do so since that does not respect the triangle inequality! Any - * old sort order will do. - */ -static int -xidComparator(const void *arg1, const void *arg2) -{ - TransactionId xid1 = *(const TransactionId *) arg1; - TransactionId xid2 = *(const TransactionId *) arg2; - - if (xid1 > xid2) - return 1; - if (xid1 < xid2) - return -1; - return 0; -} - #ifdef MULTIXACT_DEBUG static char * mxid_to_string(MultiXactId multi, int nxids, TransactionId *xids) @@ -2051,11 +2030,18 @@ multixact_redo(XLogRecPtr lsn, XLogRecord *record) if (TransactionIdPrecedes(max_xid, xids[i])) max_xid = xids[i]; } + + /* We don't expect anyone else to modify nextXid, hence startup process + * doesn't need to hold a lock while checking this. We still acquire + * the lock to modify it, though. + */ if (TransactionIdFollowsOrEquals(max_xid, ShmemVariableCache->nextXid)) { + LWLockAcquire(XidGenLock, LW_EXCLUSIVE); ShmemVariableCache->nextXid = max_xid; TransactionIdAdvance(ShmemVariableCache->nextXid); + LWLockRelease(XidGenLock); } } else |