diff options
Diffstat (limited to 'src/backend/utils/time/tqual.c')
| -rw-r--r-- | src/backend/utils/time/tqual.c | 153 |
1 files changed, 1 insertions, 152 deletions
diff --git a/src/backend/utils/time/tqual.c b/src/backend/utils/time/tqual.c index 6fbc935a6bc..b6737d40696 100644 --- a/src/backend/utils/time/tqual.c +++ b/src/backend/utils/time/tqual.c @@ -31,7 +31,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/time/tqual.c,v 1.109 2008/01/01 19:45:55 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/utils/time/tqual.c,v 1.110 2008/03/26 16:20:47 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -53,33 +53,6 @@ SnapshotData SnapshotSelfData = {HeapTupleSatisfiesSelf}; SnapshotData SnapshotAnyData = {HeapTupleSatisfiesAny}; SnapshotData SnapshotToastData = {HeapTupleSatisfiesToast}; -/* - * These SnapshotData structs are static to simplify memory allocation - * (see the hack in GetSnapshotData to avoid repeated malloc/free). - */ -static SnapshotData SerializableSnapshotData = {HeapTupleSatisfiesMVCC}; -static SnapshotData LatestSnapshotData = {HeapTupleSatisfiesMVCC}; - -/* Externally visible pointers to valid snapshots: */ -Snapshot SerializableSnapshot = NULL; -Snapshot LatestSnapshot = NULL; - -/* - * This pointer is not maintained by this module, but it's convenient - * to declare it here anyway. Callers typically assign a copy of - * GetTransactionSnapshot's result to ActiveSnapshot. - */ -Snapshot ActiveSnapshot = NULL; - -/* - * These are updated by GetSnapshotData. We initialize them this way - * for the convenience of TransactionIdIsInProgress: even in bootstrap - * mode, we don't want it to say that BootstrapTransactionId is in progress. - */ -TransactionId TransactionXmin = FirstNormalTransactionId; -TransactionId RecentXmin = FirstNormalTransactionId; -TransactionId RecentGlobalXmin = FirstNormalTransactionId; - /* local functions */ static bool XidInMVCCSnapshot(TransactionId xid, Snapshot snapshot); @@ -1236,130 +1209,6 @@ HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin, /* - * GetTransactionSnapshot - * Get the appropriate snapshot for a new query in a transaction. - * - * The SerializableSnapshot is the first one taken in a transaction. - * In serializable mode we just use that one throughout the transaction. - * In read-committed mode, we take a new snapshot each time we are called. - * - * Note that the return value points at static storage that will be modified - * by future calls and by CommandCounterIncrement(). Callers should copy - * the result with CopySnapshot() if it is to be used very long. - */ -Snapshot -GetTransactionSnapshot(void) -{ - /* First call in transaction? */ - if (SerializableSnapshot == NULL) - { - SerializableSnapshot = GetSnapshotData(&SerializableSnapshotData, true); - return SerializableSnapshot; - } - - if (IsXactIsoLevelSerializable) - return SerializableSnapshot; - - LatestSnapshot = GetSnapshotData(&LatestSnapshotData, false); - - return LatestSnapshot; -} - -/* - * GetLatestSnapshot - * Get a snapshot that is up-to-date as of the current instant, - * even if we are executing in SERIALIZABLE mode. - */ -Snapshot -GetLatestSnapshot(void) -{ - /* Should not be first call in transaction */ - if (SerializableSnapshot == NULL) - elog(ERROR, "no snapshot has been set"); - - LatestSnapshot = GetSnapshotData(&LatestSnapshotData, false); - - return LatestSnapshot; -} - -/* - * CopySnapshot - * Copy the given snapshot. - * - * The copy is palloc'd in the current memory context. - */ -Snapshot -CopySnapshot(Snapshot snapshot) -{ - Snapshot newsnap; - Size subxipoff; - Size size; - - /* We allocate any XID arrays needed in the same palloc block. */ - size = subxipoff = sizeof(SnapshotData) + - snapshot->xcnt * sizeof(TransactionId); - if (snapshot->subxcnt > 0) - size += snapshot->subxcnt * sizeof(TransactionId); - - newsnap = (Snapshot) palloc(size); - memcpy(newsnap, snapshot, sizeof(SnapshotData)); - - /* setup XID array */ - if (snapshot->xcnt > 0) - { - newsnap->xip = (TransactionId *) (newsnap + 1); - memcpy(newsnap->xip, snapshot->xip, - snapshot->xcnt * sizeof(TransactionId)); - } - else - newsnap->xip = NULL; - - /* setup subXID array */ - if (snapshot->subxcnt > 0) - { - newsnap->subxip = (TransactionId *) ((char *) newsnap + subxipoff); - memcpy(newsnap->subxip, snapshot->subxip, - snapshot->subxcnt * sizeof(TransactionId)); - } - else - newsnap->subxip = NULL; - - return newsnap; -} - -/* - * FreeSnapshot - * Free a snapshot previously copied with CopySnapshot. - * - * This is currently identical to pfree, but is provided for cleanliness. - * - * Do *not* apply this to the results of GetTransactionSnapshot or - * GetLatestSnapshot, since those are just static structs. - */ -void -FreeSnapshot(Snapshot snapshot) -{ - pfree(snapshot); -} - -/* - * FreeXactSnapshot - * Free snapshot(s) at end of transaction. - */ -void -FreeXactSnapshot(void) -{ - /* - * We do not free the xip arrays for the static snapshot structs; they - * will be reused soon. So this is now just a state change to prevent - * outside callers from accessing the snapshots. - */ - SerializableSnapshot = NULL; - LatestSnapshot = NULL; - ActiveSnapshot = NULL; /* just for cleanliness */ -} - -/* * XidInMVCCSnapshot * Is the given XID still-in-progress according to the snapshot? * |