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-rw-r--r--src/backend/utils/cache/plancache.c160
1 files changed, 76 insertions, 84 deletions
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index bbfdd888c1c..5019df6f86a 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -33,7 +33,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.15.2.1 2008/09/15 23:37:49 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.15.2.2 2008/12/13 02:00:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -70,7 +70,6 @@ static List *cached_plans_list = NIL;
static void StoreCachedPlan(CachedPlanSource *plansource, List *stmt_list,
MemoryContext plan_context);
-static List *do_planning(List *querytrees, int cursorOptions);
static void AcquireExecutorLocks(List *stmt_list, bool acquire);
static void AcquirePlannerLocks(List *stmt_list, bool acquire);
static void LockRelid(Oid relid, LOCKMODE lockmode, void *arg);
@@ -457,8 +456,8 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
*/
if (!plan)
{
+ Snapshot saveActiveSnapshot = ActiveSnapshot;
List *slist;
- TupleDesc resultDesc;
/*
* Restore the search_path that was in use when the plan was made.
@@ -467,50 +466,86 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
PushOverrideSearchPath(plansource->search_path);
/*
- * Run parse analysis and rule rewriting. The parser tends to
- * scribble on its input, so we must copy the raw parse tree to
- * prevent corruption of the cache. Note that we do not use
- * parse_analyze_varparams(), assuming that the caller never wants the
- * parameter types to change from the original values.
+ * If a snapshot is already set (the normal case), we can just use
+ * that for parsing/planning. But if it isn't, install one. We must
+ * arrange to restore ActiveSnapshot afterward, to ensure that
+ * RevalidateCachedPlan has no caller-visible effects on the
+ * snapshot. Having to replan is an unusual case, and it seems a
+ * really bad idea for RevalidateCachedPlan to affect the snapshot
+ * only in unusual cases. (Besides, the snap might have been created
+ * in a short-lived context.)
*/
- slist = pg_analyze_and_rewrite(copyObject(plansource->raw_parse_tree),
- plansource->query_string,
- plansource->param_types,
- plansource->num_params);
-
- if (plansource->fully_planned)
+ PG_TRY();
{
- /* Generate plans for queries */
- slist = do_planning(slist, plansource->cursor_options);
- }
+ Snapshot mySnapshot = NULL;
+ TupleDesc resultDesc;
- /*
- * Check or update the result tupdesc. XXX should we use a weaker
- * condition than equalTupleDescs() here?
- */
- resultDesc = PlanCacheComputeResultDesc(slist);
- if (resultDesc == NULL && plansource->resultDesc == NULL)
- {
- /* OK, doesn't return tuples */
+ if (ActiveSnapshot == NULL)
+ {
+ mySnapshot = CopySnapshot(GetTransactionSnapshot());
+ ActiveSnapshot = mySnapshot;
+ }
+
+ /*
+ * Run parse analysis and rule rewriting. The parser tends to
+ * scribble on its input, so we must copy the raw parse tree to
+ * prevent corruption of the cache. Note that we do not use
+ * parse_analyze_varparams(), assuming that the caller never wants
+ * the parameter types to change from the original values.
+ */
+ slist = pg_analyze_and_rewrite(copyObject(plansource->raw_parse_tree),
+ plansource->query_string,
+ plansource->param_types,
+ plansource->num_params);
+
+ if (plansource->fully_planned)
+ {
+ /* Generate plans for queries */
+ slist = pg_plan_queries(slist, plansource->cursor_options,
+ NULL, false);
+ }
+
+ /*
+ * Check or update the result tupdesc. XXX should we use a weaker
+ * condition than equalTupleDescs() here?
+ */
+ resultDesc = PlanCacheComputeResultDesc(slist);
+ if (resultDesc == NULL && plansource->resultDesc == NULL)
+ {
+ /* OK, doesn't return tuples */
+ }
+ else if (resultDesc == NULL || plansource->resultDesc == NULL ||
+ !equalTupleDescs(resultDesc, plansource->resultDesc))
+ {
+ MemoryContext oldcxt;
+
+ /* can we give a better error message? */
+ if (plansource->fixed_result)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cached plan must not change result type")));
+ oldcxt = MemoryContextSwitchTo(plansource->context);
+ if (resultDesc)
+ resultDesc = CreateTupleDescCopy(resultDesc);
+ if (plansource->resultDesc)
+ FreeTupleDesc(plansource->resultDesc);
+ plansource->resultDesc = resultDesc;
+ MemoryContextSwitchTo(oldcxt);
+ }
+
+ /* Done with snapshot */
+ if (mySnapshot)
+ FreeSnapshot(mySnapshot);
}
- else if (resultDesc == NULL || plansource->resultDesc == NULL ||
- !equalTupleDescs(resultDesc, plansource->resultDesc))
+ PG_CATCH();
{
- MemoryContext oldcxt;
-
- /* can we give a better error message? */
- if (plansource->fixed_result)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("cached plan must not change result type")));
- oldcxt = MemoryContextSwitchTo(plansource->context);
- if (resultDesc)
- resultDesc = CreateTupleDescCopy(resultDesc);
- if (plansource->resultDesc)
- FreeTupleDesc(plansource->resultDesc);
- plansource->resultDesc = resultDesc;
- MemoryContextSwitchTo(oldcxt);
+ /* Restore global vars and propagate error */
+ ActiveSnapshot = saveActiveSnapshot;
+ PG_RE_THROW();
}
+ PG_END_TRY();
+
+ ActiveSnapshot = saveActiveSnapshot;
/* Now we can restore current search path */
PopOverrideSearchPath();
@@ -537,49 +572,6 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
}
/*
- * Invoke the planner on some rewritten queries. This is broken out of
- * RevalidateCachedPlan just to avoid plastering "volatile" all over that
- * function's variables.
- */
-static List *
-do_planning(List *querytrees, int cursorOptions)
-{
- List *stmt_list;
-
- /*
- * If a snapshot is already set (the normal case), we can just use that
- * for planning. But if it isn't, we have to tell pg_plan_queries to make
- * a snap if it needs one. In that case we should arrange to reset
- * ActiveSnapshot afterward, to ensure that RevalidateCachedPlan has no
- * caller-visible effects on the snapshot. Having to replan is an unusual
- * case, and it seems a really bad idea for RevalidateCachedPlan to affect
- * the snapshot only in unusual cases. (Besides, the snap might have been
- * created in a short-lived context.)
- */
- if (ActiveSnapshot != NULL)
- stmt_list = pg_plan_queries(querytrees, cursorOptions, NULL, false);
- else
- {
- PG_TRY();
- {
- stmt_list = pg_plan_queries(querytrees, cursorOptions, NULL, true);
- }
- PG_CATCH();
- {
- /* Restore global vars and propagate error */
- ActiveSnapshot = NULL;
- PG_RE_THROW();
- }
- PG_END_TRY();
-
- ActiveSnapshot = NULL;
- }
-
- return stmt_list;
-}
-
-
-/*
* ReleaseCachedPlan: release active use of a cached plan.
*
* This decrements the reference count, and frees the plan if the count
generated by cgit v1.2.3 (git 2.46.0) at 2025-09-20 09:32:47 +0000