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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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43
src/backend/executor/execMain.c
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@ -26,7 +26,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.219 2003/09/25 18:58:35 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.220 2003/10/01 21:30:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -104,8 +104,14 @@ static void EvalPlanQualStop(evalPlanQual *epq);
* field of the QueryDesc is filled in to describe the tuples that will be
* returned, and the internal fields (estate and planstate) are set up.
*
* If useSnapshotNow is true, run the query with SnapshotNow time qual rules
* instead of the normal use of QuerySnapshot.
* If useCurrentSnapshot is true, run the query with the latest available
* snapshot, instead of the normal QuerySnapshot. Also, if it's an update
* or delete query, check that the rows to be updated or deleted would be
* visible to the normal QuerySnapshot. (This is a special-case behavior
* needed for referential integrity updates in serializable transactions.
* We must check all currently-committed rows, but we want to throw a
* can't-serialize error if any rows that would need updates would not be
* visible under the normal serializable snapshot.)
*
* If explainOnly is true, we are not actually intending to run the plan,
* only to set up for EXPLAIN; so skip unwanted side-effects.
@ -115,7 +121,7 @@ static void EvalPlanQualStop(evalPlanQual *epq);
* ----------------------------------------------------------------
*/
void
ExecutorStart(QueryDesc *queryDesc, bool useSnapshotNow, bool explainOnly)
ExecutorStart(QueryDesc *queryDesc, bool useCurrentSnapshot, bool explainOnly)
{
EState *estate;
MemoryContext oldcontext;
@ -157,15 +163,18 @@ ExecutorStart(QueryDesc *queryDesc, bool useSnapshotNow, bool explainOnly)
* the life of this query, even if it outlives the current command and
* current snapshot.
*/
if (useSnapshotNow)
if (useCurrentSnapshot)
{
estate->es_snapshot = SnapshotNow;
estate->es_snapshot_cid = GetCurrentCommandId();
/* RI update/delete query --- must use an up-to-date snapshot */
estate->es_snapshot = CopyCurrentSnapshot();
/* crosscheck updates/deletes against transaction snapshot */
estate->es_crosscheck_snapshot = CopyQuerySnapshot();
}
else
{
/* normal query --- use query snapshot, no crosscheck */
estate->es_snapshot = CopyQuerySnapshot();
estate->es_snapshot_cid = estate->es_snapshot->curcid;
estate->es_crosscheck_snapshot = SnapshotAny;
}
/*
@ -1118,7 +1127,7 @@ lnext: ;
tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
test = heap_mark4update(erm->relation, &tuple, &buffer,
estate->es_snapshot_cid);
estate->es_snapshot->curcid);
ReleaseBuffer(buffer);
switch (test)
{
@ -1278,7 +1287,7 @@ ExecSelect(TupleTableSlot *slot,
if (estate->es_into_relation_descriptor != NULL)
{
heap_insert(estate->es_into_relation_descriptor, tuple,
estate->es_snapshot_cid);
estate->es_snapshot->curcid);
IncrAppended();
}
@ -1354,7 +1363,7 @@ ExecInsert(TupleTableSlot *slot,
* insert the tuple
*/
newId = heap_insert(resultRelationDesc, tuple,
estate->es_snapshot_cid);
estate->es_snapshot->curcid);
IncrAppended();
(estate->es_processed)++;
@ -1406,7 +1415,7 @@ ExecDelete(TupleTableSlot *slot,
bool dodelete;
dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
estate->es_snapshot_cid);
estate->es_snapshot->curcid);
if (!dodelete) /* "do nothing" */
return;
@ -1418,7 +1427,8 @@ ExecDelete(TupleTableSlot *slot,
ldelete:;
result = heap_delete(resultRelationDesc, tupleid,
&ctid,
estate->es_snapshot_cid,
estate->es_snapshot->curcid,
estate->es_crosscheck_snapshot,
true /* wait for commit */);
switch (result)
{
@ -1517,7 +1527,7 @@ ExecUpdate(TupleTableSlot *slot,
newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
tupleid, tuple,
estate->es_snapshot_cid);
estate->es_snapshot->curcid);
if (newtuple == NULL) /* "do nothing" */
return;
@ -1553,7 +1563,8 @@ lreplace:;
*/
result = heap_update(resultRelationDesc, tupleid, tuple,
&ctid,
estate->es_snapshot_cid,
estate->es_snapshot->curcid,
estate->es_crosscheck_snapshot,
true /* wait for commit */);
switch (result)
{
@ -2039,7 +2050,7 @@ EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
*/
epqstate->es_direction = ForwardScanDirection;
epqstate->es_snapshot = estate->es_snapshot;
epqstate->es_snapshot_cid = estate->es_snapshot_cid;
epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
epqstate->es_range_table = estate->es_range_table;
epqstate->es_result_relations = estate->es_result_relations;
epqstate->es_num_result_relations = estate->es_num_result_relations;