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Fix caching of foreign-key-checking queries so that when a replan is needed,

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we regenerate the SQL query text not merely the plan derived from it.  This
is needed to handle contingencies such as renaming of a table or column
used in an FK.  Pre-8.3, such cases worked despite the lack of replanning
(because the cached plan needn't actually change), so this is a regression.
Per bug #4417 from Benjamin Bihler.
This commit is contained in:
Tom Lane
2008-09-15 23:37:40 +00:00
parent 448950b37b
commit 1cd935609f
5 changed files with 103 additions and 7 deletions
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40
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 1.21 2008/09/09 18:58:08 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.22 2008/09/15 23:37:39 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -571,6 +571,44 @@ ReleaseCachedPlan(CachedPlan *plan, bool useResOwner)
MemoryContextDelete(plan->context);
}
/*
* CachedPlanIsValid: test whether the plan within a CachedPlanSource is
* currently valid (that is, not marked as being in need of revalidation).
*
* This result is only trustworthy (ie, free from race conditions) if
* the caller has acquired locks on all the relations used in the plan.
*/
bool
CachedPlanIsValid(CachedPlanSource *plansource)
{
CachedPlan *plan;
/* Validity check that we were given a CachedPlanSource */
Assert(list_member_ptr(cached_plans_list, plansource));
plan = plansource->plan;
if (plan && !plan->dead)
{
/*
* Plan must have positive refcount because it is referenced by
* plansource; so no need to fear it disappears under us here.
*/
Assert(plan->refcount > 0);
/*
* Although we don't want to acquire locks here, it still seems
* useful to check for expiration of a transient plan.
*/
if (TransactionIdIsValid(plan->saved_xmin) &&
!TransactionIdEquals(plan->saved_xmin, TransactionXmin))
plan->dead = true;
else
return true;
}
return false;
}
/*
* AcquireExecutorLocks: acquire locks needed for execution of a fully-planned
* cached plan; or release them if acquire is false.