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Repair RI trigger visibility problems (this time for sure ;-)) per recent

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discussion on pgsql-hackers: in READ COMMITTED mode we just have to force
a QuerySnapshot update in the trigger, but in SERIALIZABLE mode we have
to run the scan under a current snapshot and then complain if any rows
would be updated/deleted that are not visible in the transaction snapshot.
This commit is contained in:
Tom Lane
2003-10-01 21:30:53 +00:00
parent 6099bc03f3
commit 55d85f42a8
15 changed files with 210 additions and 84 deletions
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60
src/backend/utils/time/tqual.c
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@@ -16,7 +16,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.69 2003/09/25 18:58:35 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.70 2003/10/01 21:30:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -26,14 +26,19 @@
#include "storage/sinval.h"
#include "utils/tqual.h"
static SnapshotData SnapshotDirtyData;
Snapshot SnapshotDirty = &SnapshotDirtyData;
/*
* The SnapshotData structs are static to simplify memory allocation
* (see the hack in GetSnapshotData to avoid repeated malloc/free).
*/
static SnapshotData QuerySnapshotData;
static SnapshotData SerializableSnapshotData;
static SnapshotData CurrentSnapshotData;
static SnapshotData SnapshotDirtyData;
/* Externally visible pointers to valid snapshots: */
Snapshot QuerySnapshot = NULL;
Snapshot SerializableSnapshot = NULL;
Snapshot SnapshotDirty = &SnapshotDirtyData;
/* These are updated by GetSnapshotData: */
TransactionId RecentXmin = InvalidTransactionId;
@@ -387,10 +392,8 @@ HeapTupleSatisfiesToast(HeapTupleHeader tuple)
* CurrentCommandId.
*/
int
HeapTupleSatisfiesUpdate(HeapTuple htuple, CommandId curcid)
HeapTupleSatisfiesUpdate(HeapTupleHeader tuple, CommandId curcid)
{
HeapTupleHeader tuple = htuple->t_data;
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
@@ -1023,6 +1026,42 @@ CopyQuerySnapshot(void)
return snapshot;
}
/*
* CopyCurrentSnapshot
* Make a snapshot that is up-to-date as of the current instant,
* and return a copy.
*
* The copy is palloc'd in the current memory context.
*/
Snapshot
CopyCurrentSnapshot(void)
{
Snapshot currentSnapshot;
Snapshot snapshot;
if (QuerySnapshot == NULL) /* should not be first call in xact */
elog(ERROR, "no snapshot has been set");
/* Update the static struct */
currentSnapshot = GetSnapshotData(&CurrentSnapshotData, false);
currentSnapshot->curcid = GetCurrentCommandId();
/* Make a copy */
snapshot = (Snapshot) palloc(sizeof(SnapshotData));
memcpy(snapshot, currentSnapshot, sizeof(SnapshotData));
if (snapshot->xcnt > 0)
{
snapshot->xip = (TransactionId *)
palloc(snapshot->xcnt * sizeof(TransactionId));
memcpy(snapshot->xip, currentSnapshot->xip,
snapshot->xcnt * sizeof(TransactionId));
}
else
snapshot->xip = NULL;
return snapshot;
}
/*
* FreeXactSnapshot
* Free snapshot(s) at end of transaction.
@@ -1031,8 +1070,9 @@ void
FreeXactSnapshot(void)
{
/*
* We do not free(QuerySnapshot->xip); or
* free(SerializableSnapshot->xip); they will be reused soon
* We do not free the xip arrays for the snapshot structs;
* they will be reused soon. So this is now just a state
* change to prevent outside callers from accessing the snapshots.
*/
QuerySnapshot = NULL;
SerializableSnapshot = NULL;