diff options
Diffstat (limited to 'src/backend/access/transam/varsup.c')
| -rw-r--r-- | src/backend/access/transam/varsup.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c index 857f2c3d3e8..a1144a2a79d 100644 --- a/src/backend/access/transam/varsup.c +++ b/src/backend/access/transam/varsup.c @@ -6,7 +6,7 @@ * Copyright (c) 2000, PostgreSQL Global Development Group * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.42 2001/07/16 22:43:33 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.43 2001/08/10 18:57:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -105,11 +105,26 @@ ReadNewTransactionId(TransactionId *xid) static Oid lastSeenOid = InvalidOid; -void -GetNewObjectId(Oid *oid_return) +Oid +GetNewObjectId(void) { + Oid result; + SpinAcquire(OidGenLockId); + /* + * Check for wraparound of the OID counter. We *must* not return 0 + * (InvalidOid); and as long as we have to check that, it seems a good + * idea to skip over everything below BootstrapObjectIdData too. (This + * basically just reduces the odds of OID collision right after a wrap + * occurs.) Note we are relying on unsigned comparison here. + */ + if (ShmemVariableCache->nextOid < ((Oid) BootstrapObjectIdData)) + { + ShmemVariableCache->nextOid = BootstrapObjectIdData; + ShmemVariableCache->oidCount = 0; + } + /* If we run out of logged for use oids then we must log more */ if (ShmemVariableCache->oidCount == 0) { @@ -117,13 +132,16 @@ GetNewObjectId(Oid *oid_return) ShmemVariableCache->oidCount = VAR_OID_PREFETCH; } - if (PointerIsValid(oid_return)) - lastSeenOid = (*oid_return) = ShmemVariableCache->nextOid; + result = ShmemVariableCache->nextOid; (ShmemVariableCache->nextOid)++; (ShmemVariableCache->oidCount)--; SpinRelease(OidGenLockId); + + lastSeenOid = result; + + return result; } void @@ -159,8 +177,8 @@ CheckMaxObjectId(Oid assigned_oid) */ XLogPutNextOid(assigned_oid + VAR_OID_PREFETCH); - ShmemVariableCache->oidCount = VAR_OID_PREFETCH - 1; ShmemVariableCache->nextOid = assigned_oid + 1; + ShmemVariableCache->oidCount = VAR_OID_PREFETCH - 1; SpinRelease(OidGenLockId); } |