diff options
Diffstat (limited to 'src/backend/access/transam/varsup.c')
| -rw-r--r-- | src/backend/access/transam/varsup.c | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c index 885e8e236c..e4271f5fa8 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 1.35 2001/01/24 19:42:51 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.36 2001/03/13 01:17:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -14,12 +14,17 @@ #include "postgres.h" #include "access/transam.h" +#include "access/xlog.h" #include "storage/proc.h" -SPINLOCK OidGenLockId; -extern SPINLOCK XidGenLockId; -extern void XLogPutNextOid(Oid nextOid); +/* Number of XIDs and OIDs to prefetch (preallocate) per XLOG write */ +#define VAR_XID_PREFETCH 1024 +#define VAR_OID_PREFETCH 8192 + +/* Spinlocks for serializing generation of XIDs and OIDs, respectively */ +SPINLOCK XidGenLockId; +SPINLOCK OidGenLockId; /* pointer to "variable cache" in shared memory (set up by shmem.c) */ VariableCache ShmemVariableCache = NULL; @@ -38,23 +43,31 @@ GetNewTransactionId(TransactionId *xid) } SpinAcquire(XidGenLockId); + + /* If we run out of logged for use xids then we must log more */ + if (ShmemVariableCache->xidCount == 0) + { + XLogPutNextXid(ShmemVariableCache->nextXid + VAR_XID_PREFETCH); + ShmemVariableCache->xidCount = VAR_XID_PREFETCH; + } + *xid = ShmemVariableCache->nextXid; - (ShmemVariableCache->nextXid)++; - if (MyProc != (PROC *) NULL) - MyProc->xid = *xid; + (ShmemVariableCache->nextXid)++; + (ShmemVariableCache->xidCount)--; SpinRelease(XidGenLockId); + if (MyProc != (PROC *) NULL) + MyProc->xid = *xid; } /* - * Like GetNewTransactionId reads nextXid but don't fetch it. + * Read nextXid but don't allocate it. */ void ReadNewTransactionId(TransactionId *xid) { - /* * During bootstrap initialization, we return the special * bootstrap transaction id. @@ -68,7 +81,6 @@ ReadNewTransactionId(TransactionId *xid) SpinAcquire(XidGenLockId); *xid = ShmemVariableCache->nextXid; SpinRelease(XidGenLockId); - } /* ---------------------------------------------------------------- @@ -76,7 +88,6 @@ ReadNewTransactionId(TransactionId *xid) * ---------------------------------------------------------------- */ -#define VAR_OID_PREFETCH 8192 static Oid lastSeenOid = InvalidOid; void @@ -84,7 +95,7 @@ GetNewObjectId(Oid *oid_return) { SpinAcquire(OidGenLockId); - /* If we run out of logged for use oids then we log more */ + /* If we run out of logged for use oids then we must log more */ if (ShmemVariableCache->oidCount == 0) { XLogPutNextOid(ShmemVariableCache->nextOid + VAR_OID_PREFETCH); @@ -103,11 +114,11 @@ GetNewObjectId(Oid *oid_return) void CheckMaxObjectId(Oid assigned_oid) { - if (lastSeenOid != InvalidOid && assigned_oid < lastSeenOid) return; SpinAcquire(OidGenLockId); + if (assigned_oid < ShmemVariableCache->nextOid) { lastSeenOid = ShmemVariableCache->nextOid - 1; @@ -138,5 +149,4 @@ CheckMaxObjectId(Oid assigned_oid) ShmemVariableCache->nextOid = assigned_oid + 1; SpinRelease(OidGenLockId); - } |