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Force READY portals into FAILED state when a transaction or subtransaction

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is aborted, if they were created within the failed xact.  This prevents
ExecutorEnd from being run on them, which is a good idea because they may
contain references to tables or other objects that no longer exist.
In particular this is hazardous when auto_explain is active, but it's
really rather surprising that nobody has seen an issue with this before.
I'm back-patching this to 8.4, since that's the first version that contains
auto_explain or an ExecutorEnd hook, but I wonder whether we shouldn't
back-patch further.
This commit is contained in:
Tom Lane 2010-02-18 03:06:53 +00:00
parent ef7604fafa
commit 85a646aee3
1 changed files with 40 additions and 50 deletions
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90
src/backend/utils/mmgr/portalmem.c
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@ -12,7 +12,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.113.2.2 2010/01/18 02:30:30 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.113.2.3 2010/02/18 03:06:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -668,6 +668,7 @@ AtAbort_Portals(void)
{
Portal portal = hentry->portal;
/* Any portal that was actually running has to be considered broken */
if (portal->status == PORTAL_ACTIVE)
portal->status = PORTAL_FAILED;
@ -677,6 +678,15 @@ AtAbort_Portals(void)
if (portal->createSubid == InvalidSubTransactionId)
continue;
/*
* If it was created in the current transaction, we can't do normal
* shutdown on a READY portal either; it might refer to objects
* created in the failed transaction. See comments in
* AtSubAbort_Portals.
*/
if (portal->status == PORTAL_READY)
portal->status = PORTAL_FAILED;
/* let portalcmds.c clean up the state it knows about */
if (PointerIsValid(portal->cleanup))
{
@ -789,61 +799,41 @@ AtSubAbort_Portals(SubTransactionId mySubid,
continue;
/*
* Force any active portals of my own transaction into FAILED state.
* This is mostly to ensure that a portal running a FETCH will go
* FAILED if the underlying cursor fails. (Note we do NOT want to do
* this to upper-level portals, since they may be able to continue.)
*
* This is only needed to dodge the sanity check in PortalDrop.
* Force any live portals of my own subtransaction into FAILED state.
* We have to do this because they might refer to objects created or
* changed in the failed subtransaction, leading to crashes if
* execution is resumed, or even if we just try to run ExecutorEnd.
* (Note we do NOT do this to upper-level portals, since they cannot
* have such references and hence may be able to continue.)
*/
if (portal->status == PORTAL_ACTIVE)
if (portal->status == PORTAL_READY ||
portal->status == PORTAL_ACTIVE)
portal->status = PORTAL_FAILED;
/* let portalcmds.c clean up the state it knows about */
if (PointerIsValid(portal->cleanup))
{
(*portal->cleanup) (portal);
portal->cleanup = NULL;
}
/* drop cached plan reference, if any */
PortalReleaseCachedPlan(portal);
/*
* If the portal is READY then allow it to survive into the parent
* transaction; otherwise shut it down.
*
* Currently, we can't actually support that because the portal's
* query might refer to objects created or changed in the failed
* subtransaction, leading to crashes if execution is resumed. So,
* even READY portals are deleted. It would be nice to detect whether
* the query actually depends on any such object, instead.
* Any resources belonging to the portal will be released in the
* upcoming transaction-wide cleanup; they will be gone before we
* run PortalDrop.
*/
#ifdef NOT_USED
if (portal->status == PORTAL_READY)
{
portal->createSubid = parentSubid;
if (portal->resowner)
ResourceOwnerNewParent(portal->resowner, parentXactOwner);
}
else
#endif
{
/* let portalcmds.c clean up the state it knows about */
if (PointerIsValid(portal->cleanup))
{
(*portal->cleanup) (portal);
portal->cleanup = NULL;
}
portal->resowner = NULL;
/* drop cached plan reference, if any */
PortalReleaseCachedPlan(portal);
/*
* Any resources belonging to the portal will be released in the
* upcoming transaction-wide cleanup; they will be gone before we
* run PortalDrop.
*/
portal->resowner = NULL;
/*
* Although we can't delete the portal data structure proper, we
* can release any memory in subsidiary contexts, such as executor
* state. The cleanup hook was the last thing that might have
* needed data there.
*/
MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
}
/*
* Although we can't delete the portal data structure proper, we
* can release any memory in subsidiary contexts, such as executor
* state. The cleanup hook was the last thing that might have
* needed data there.
*/
MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
}
}