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Fix a many-legged critter reported by chifungfan@yahoo.com: under the

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right circumstances a hash join executed as a DECLARE CURSOR/FETCH
query would crash the backend.  Problem as seen in current sources was
that the hash tables were stored in a context that was a child of
TransactionCommandContext, which got zapped at completion of the FETCH
command --- but cursor cleanup executed at COMMIT expected the tables
to still be valid.  I haven't chased down the details as seen in 7.0.*
but I'm sure it's the same general problem.
This commit is contained in:
Tom Lane
2000-08-22 04:06:22 +00:00
parent 94e90d9a86
commit 0147b1934f
7 changed files with 84 additions and 51 deletions
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42
src/backend/executor/execMain.c
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@ -27,7 +27,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.123 2000/08/06 04:26:26 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.124 2000/08/22 04:06:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1574,31 +1574,32 @@ ExecRelCheck(Relation rel, TupleTableSlot *slot, EState *estate)
{
int ncheck = rel->rd_att->constr->num_check;
ConstrCheck *check = rel->rd_att->constr->check;
MemoryContext oldContext;
ExprContext *econtext;
MemoryContext oldContext;
List *qual;
int i;
/*
* Make sure econtext, expressions, etc are placed in appropriate context.
* We will use the EState's per-tuple context for evaluating constraint
* expressions. Create it if it's not already there; if it is, reset it
* to free previously-used storage.
*/
oldContext = MemoryContextSwitchTo(TransactionCommandContext);
/*
* Create or reset the exprcontext for evaluating constraint expressions.
*/
econtext = estate->es_constraint_exprcontext;
econtext = estate->es_per_tuple_exprcontext;
if (econtext == NULL)
estate->es_constraint_exprcontext = econtext =
MakeExprContext(NULL, TransactionCommandContext);
{
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
estate->es_per_tuple_exprcontext = econtext =
MakeExprContext(NULL, estate->es_query_cxt);
MemoryContextSwitchTo(oldContext);
}
else
ResetExprContext(econtext);
/*
* If first time through for current result relation, set up econtext's
* range table to refer to result rel, and build expression nodetrees
* for rel's constraint expressions. All this stuff is kept in
* TransactionCommandContext so it will still be here next time through.
* for rel's constraint expressions. All this stuff is kept in the
* per-query memory context so it will still be here next time through.
*
* NOTE: if there are multiple result relations (eg, due to inheritance)
* then we leak storage for prior rel's expressions and rangetable.
@ -1608,7 +1609,14 @@ ExecRelCheck(Relation rel, TupleTableSlot *slot, EState *estate)
if (econtext->ecxt_range_table == NIL ||
getrelid(1, econtext->ecxt_range_table) != RelationGetRelid(rel))
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
RangeTblEntry *rte;
/*
* Make sure expressions, etc are placed in appropriate context.
*/
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
rte = makeNode(RangeTblEntry);
rte->relname = RelationGetRelationName(rel);
rte->ref = makeNode(Attr);
@ -1627,10 +1635,10 @@ ExecRelCheck(Relation rel, TupleTableSlot *slot, EState *estate)
qual = (List *) stringToNode(check[i].ccbin);
estate->es_result_relation_constraints[i] = qual;
}
}
/* Done with building long-lived items */
MemoryContextSwitchTo(oldContext);
/* Done with building long-lived items */
MemoryContextSwitchTo(oldContext);
}
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;