>>>>> "Tom" == Tom Lane <t...@sss.pgh.pa.us> writes:
Tom> If we're going to do that, I think it needs to be in 9.4. Are
Tom> you going to work up a patch?
How's this? (applies and passes regression on 9.4 and master)
--
Andrew (irc:RhodiumToad)
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 09ff035..0388735 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -2199,44 +2199,56 @@ AggGetAggref(FunctionCallInfo fcinfo)
}
/*
- * AggGetPerTupleEContext - fetch per-input-tuple ExprContext
+ * AggGetTempMemoryContext - fetch short-term memory context
*
- * This is useful in agg final functions; the econtext returned is the
- * same per-tuple context that the transfn was called in (which can
- * safely get reset during the final function).
+ * This is useful in agg final functions; the context returned is one that the
+ * final function can safely reset as desired. This isn't useful for transition
+ * functions, since the context returned MAY (we don't promise) be the same as
+ * the context those are called in.
*
* As above, this is currently not useful for aggs called as window functions.
*/
-ExprContext *
-AggGetPerTupleEContext(FunctionCallInfo fcinfo)
+MemoryContext
+AggGetTempMemoryContext(FunctionCallInfo fcinfo)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
AggState *aggstate = (AggState *) fcinfo->context;
- return aggstate->tmpcontext;
+ return aggstate->tmpcontext->ecxt_per_tuple_memory;
}
return NULL;
}
/*
- * AggGetPerAggEContext - fetch per-output-tuple ExprContext
+ * AggRegisterCallback - register a cleanup callback linked to aggcontext
*
* This is useful for aggs to register shutdown callbacks, which will ensure
- * that non-memory resources are freed.
+ * that non-memory resources are freed. These callbacks will occur just before
+ * the associated aggcontext (as returned by AggCheckCallContext) is reset,
+ * either between groups or as a result of rescanning the query. They will NOT
+ * be called on error paths. The primary intent is to allow for freeing of
+ * tuplestores or tuplesorts maintained in aggcontext, or pins held by slots
+ * created by the agg functions. (They will not be called until after the
+ * result of the finalfn is no longer needed, so it's safe for the finalfn to
+ * return data that will be freed by the callback.)
*
* As above, this is currently not useful for aggs called as window functions.
*/
-ExprContext *
-AggGetPerAggEContext(FunctionCallInfo fcinfo)
+void
+AggRegisterCallback(FunctionCallInfo fcinfo,
+ ExprContextCallbackFunction func,
+ Datum arg)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
AggState *aggstate = (AggState *) fcinfo->context;
- return aggstate->ss.ps.ps_ExprContext;
+ RegisterExprContextCallback(aggstate->ss.ps.ps_ExprContext, func, arg);
+
+ return;
}
- return NULL;
+ elog(ERROR,"Aggregate function cannot register a callback in this context");
}
diff --git a/src/backend/utils/adt/orderedsetaggs.c b/src/backend/utils/adt/orderedsetaggs.c
index efb0411..d116a63 100644
--- a/src/backend/utils/adt/orderedsetaggs.c
+++ b/src/backend/utils/adt/orderedsetaggs.c
@@ -49,8 +49,6 @@ typedef struct OSAPerQueryState
MemoryContext qcontext;
/* Memory context containing per-group data: */
MemoryContext gcontext;
- /* Agg plan node's output econtext: */
- ExprContext *peraggecontext;
/* These fields are used only when accumulating tuples: */
@@ -117,7 +115,6 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
Aggref *aggref;
MemoryContext qcontext;
MemoryContext gcontext;
- ExprContext *peraggecontext;
List *sortlist;
int numSortCols;
@@ -133,10 +130,6 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
elog(ERROR, "ordered-set aggregate called in non-aggregate context");
if (!AGGKIND_IS_ORDERED_SET(aggref->aggkind))
elog(ERROR, "ordered-set aggregate support function called for non-ordered-set aggregate");
- /* Also get output exprcontext so we can register shutdown callback */
- peraggecontext = AggGetPerAggEContext(fcinfo);
- if (!peraggecontext)
- elog(ERROR, "ordered-set aggregate called in non-aggregate context");
/*
* Prepare per-query structures in the fn_mcxt, which we assume is the
@@ -150,7 +143,6 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
qstate->aggref = aggref;
qstate->qcontext = qcontext;
qstate->gcontext = gcontext;
- qstate->peraggecontext = peraggecontext;
/* Extract the sort information */
sortlist = aggref->aggorder;
@@ -291,9 +283,9 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
osastate->number_of_rows = 0;
/* Now register a shutdown callback to clean things up */
- RegisterExprContextCallback(qstate->peraggecontext,
- ordered_set_shutdown,
- PointerGetDatum(osastate));
+ AggRegisterCallback(fcinfo,
+ ordered_set_shutdown,
+ PointerGetDatum(osastate));
MemoryContextSwitchTo(oldcontext);
@@ -1310,7 +1302,7 @@ hypothetical_dense_rank_final(PG_FUNCTION_ARGS)
sortColIdx = osastate->qstate->sortColIdx;
/* Get short-term context we can use for execTuplesMatch */
- tmpcontext = AggGetPerTupleEContext(fcinfo)->ecxt_per_tuple_memory;
+ tmpcontext = AggGetTempMemoryContext(fcinfo);
/* insert the hypothetical row into the sort */
slot = osastate->qstate->tupslot;
diff --git a/src/include/fmgr.h b/src/include/fmgr.h
index 267403c..9324dba 100644
--- a/src/include/fmgr.h
+++ b/src/include/fmgr.h
@@ -24,6 +24,7 @@ typedef struct Aggref *fmAggrefPtr;
/* Likewise, avoid including execnodes.h here */
typedef struct ExprContext *fmExprContextPtr;
+typedef void (*fmExprContextCallbackFunction) (Datum arg);
/* Likewise, avoid including stringinfo.h here */
typedef struct StringInfoData *fmStringInfo;
@@ -656,8 +657,10 @@ extern void **find_rendezvous_variable(const char *varName);
extern int AggCheckCallContext(FunctionCallInfo fcinfo,
MemoryContext *aggcontext);
extern fmAggrefPtr AggGetAggref(FunctionCallInfo fcinfo);
-extern fmExprContextPtr AggGetPerTupleEContext(FunctionCallInfo fcinfo);
-extern fmExprContextPtr AggGetPerAggEContext(FunctionCallInfo fcinfo);
+extern MemoryContext AggGetTempMemoryContext(FunctionCallInfo fcinfo);
+extern void AggRegisterCallback(FunctionCallInfo fcinfo,
+ fmExprContextCallbackFunction func,
+ Datum arg);
/*
* We allow plugin modules to hook function entry/exit. This is intended
--
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