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Fix failure to ensure that a snapshot is available to datatype input functions

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when they are invoked by the parser.  We had been setting up a snapshot at
plan time but really it needs to be done earlier, before parse analysis.
Per report from Dmitry Koterov.

Also fix two related problems discovered while poking at this one:
exec_bind_message called datatype input functions without establishing a
snapshot, and SET CONSTRAINTS IMMEDIATE could call trigger functions without
establishing a snapshot.

Backpatch to 8.2.  The underlying problem goes much further back, but it is
masked in 8.1 and before because we didn't attempt to invoke domain check
constraints within datatype input.  It would only be exposed if a C-language
datatype input function used the snapshot; which evidently none do, or we'd
have heard complaints sooner.  Since this code has changed a lot over time,
a back-patch is hardly risk-free, and so I'm disinclined to patch further
than absolutely necessary.
This commit is contained in:
Tom Lane
2008-12-13 02:00:20 +00:00
parent 0f864a63ea
commit c98a923786
5 changed files with 145 additions and 14 deletions
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26
src/backend/utils/cache/plancache.c vendored
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@ -35,7 +35,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.23 2008/10/04 21:56:54 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.24 2008/12/13 02:00:20 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -463,6 +463,7 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
*/
if (!plan)
{
bool snapshot_set = false;
List *slist;
TupleDesc resultDesc;
@ -472,6 +473,19 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
*/
PushOverrideSearchPath(plansource->search_path);
/*
* If a snapshot is already set (the normal case), we can just use
* that for parsing/planning. But if it isn't, install one. Note:
* no point in checking whether parse analysis requires a snapshot;
* utility commands don't have invalidatable plans, so we'd not get
* here for such a command.
*/
if (!ActiveSnapshotSet())
{
PushActiveSnapshot(GetTransactionSnapshot());
snapshot_set = true;
}
/*
* Run parse analysis and rule rewriting. The parser tends to
* scribble on its input, so we must copy the raw parse tree to
@ -488,13 +502,9 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
{
/*
* Generate plans for queries.
*
* 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.
*/
slist = pg_plan_queries(slist, plansource->cursor_options,
NULL, !ActiveSnapshotSet());
NULL, false);
}
/*
@ -525,6 +535,10 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
MemoryContextSwitchTo(oldcxt);
}
/* Release snapshot if we got one */
if (snapshot_set)
PopActiveSnapshot();
/* Now we can restore current search path */
PopOverrideSearchPath();