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Fix domain_in() bug exhibited by Darcy Buskermolen. The idea of an EState

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that's shorter-lived than the expression state being evaluated in it really
doesn't work :-( --- we end up with fn_extra caches getting deleted while
still in use.  Rather than abandon the notion of caching expression state
across domain_in calls altogether, I chose to make domain_in a bit cozier
with ExprContext.  All we really need for evaluating variable-free
expressions is an ExprContext, not an EState, so I invented the notion of a
"standalone" ExprContext.  domain_in can prevent resource leakages by doing
a ReScanExprContext on this rather than having to free it entirely; so we
can make the ExprContext have the same lifespan (and particularly the same
per_query memory context) as the expression state structs.
This commit is contained in:
Tom Lane
2006-08-04 21:33:36 +00:00
parent bf7b205e16
commit c68489863c
4 changed files with 105 additions and 32 deletions
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71
src/backend/executor/execUtils.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.138 2006/07/31 20:09:04 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.139 2006/08/04 21:33:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -17,6 +17,7 @@
* CreateExecutorState Create/delete executor working state
* FreeExecutorState
* CreateExprContext
* CreateStandaloneExprContext
* FreeExprContext
* ReScanExprContext
*
@ -331,6 +332,68 @@ CreateExprContext(EState *estate)
return econtext;
}
/* ----------------
* CreateStandaloneExprContext
*
* Create a context for standalone expression evaluation.
*
* An ExprContext made this way can be used for evaluation of expressions
* that contain no Params, subplans, or Var references (it might work to
* put tuple references into the scantuple field, but it seems unwise).
*
* The ExprContext struct is allocated in the caller's current memory
* context, which also becomes its "per query" context.
*
* It is caller's responsibility to free the ExprContext when done,
* or at least ensure that any shutdown callbacks have been called
* (ReScanExprContext() is suitable). Otherwise, non-memory resources
* might be leaked.
* ----------------
*/
ExprContext *
CreateStandaloneExprContext(void)
{
ExprContext *econtext;
/* Create the ExprContext node within the caller's memory context */
econtext = makeNode(ExprContext);
/* Initialize fields of ExprContext */
econtext->ecxt_scantuple = NULL;
econtext->ecxt_innertuple = NULL;
econtext->ecxt_outertuple = NULL;
econtext->ecxt_per_query_memory = CurrentMemoryContext;
/*
* Create working memory for expression evaluation in this context.
*/
econtext->ecxt_per_tuple_memory =
AllocSetContextCreate(CurrentMemoryContext,
"ExprContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
econtext->ecxt_param_exec_vals = NULL;
econtext->ecxt_param_list_info = NULL;
econtext->ecxt_aggvalues = NULL;
econtext->ecxt_aggnulls = NULL;
econtext->caseValue_datum = (Datum) 0;
econtext->caseValue_isNull = true;
econtext->domainValue_datum = (Datum) 0;
econtext->domainValue_isNull = true;
econtext->ecxt_estate = NULL;
econtext->ecxt_callbacks = NULL;
return econtext;
}
/* ----------------
* FreeExprContext
*
@ -352,9 +415,11 @@ FreeExprContext(ExprContext *econtext)
ShutdownExprContext(econtext);
/* And clean up the memory used */
MemoryContextDelete(econtext->ecxt_per_tuple_memory);
/* Unlink self from owning EState */
/* Unlink self from owning EState, if any */
estate = econtext->ecxt_estate;
estate->es_exprcontexts = list_delete_ptr(estate->es_exprcontexts, econtext);
if (estate)
estate->es_exprcontexts = list_delete_ptr(estate->es_exprcontexts,
econtext);
/* And delete the ExprContext node */
pfree(econtext);
}