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Restructure error handling as recently discussed. It is now really

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possible to trap an error inside a function rather than letting it
propagate out to PostgresMain.  You still have to use AbortCurrentTransaction
to clean up, but at least the error handling itself will cooperate.
This commit is contained in:
Tom Lane
2004-07-31 00:45:57 +00:00
parent 94f8f63fdb
commit a393fbf937
20 changed files with 1598 additions and 1525 deletions
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157
src/backend/commands/portalcmds.c
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@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.29 2004/07/17 03:28:47 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.30 2004/07/31 00:45:31 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -259,8 +259,18 @@ PortalCleanup(Portal portal)
/* We must make the portal's resource owner current */
saveResourceOwner = CurrentResourceOwner;
CurrentResourceOwner = portal->resowner;
ExecutorEnd(queryDesc);
PG_TRY();
{
CurrentResourceOwner = portal->resowner;
ExecutorEnd(queryDesc);
}
PG_CATCH();
{
/* Ensure CurrentResourceOwner is restored on error */
CurrentResourceOwner = saveResourceOwner;
PG_RE_THROW();
}
PG_END_TRY();
CurrentResourceOwner = saveResourceOwner;
}
}
@ -317,86 +327,95 @@ PersistHoldablePortal(Portal portal)
portal->status = PORTAL_ACTIVE;
/*
* Set global portal context pointers.
* Set up global portal context pointers.
*/
saveActivePortal = ActivePortal;
ActivePortal = portal;
saveResourceOwner = CurrentResourceOwner;
CurrentResourceOwner = portal->resowner;
savePortalContext = PortalContext;
PortalContext = PortalGetHeapMemory(portal);
saveQueryContext = QueryContext;
QueryContext = portal->queryContext;
MemoryContextSwitchTo(PortalContext);
/*
* Rewind the executor: we need to store the entire result set in the
* tuplestore, so that subsequent backward FETCHs can be processed.
*/
ExecutorRewind(queryDesc);
/* Change the destination to output to the tuplestore */
queryDesc->dest = CreateDestReceiver(Tuplestore, portal);
/* Fetch the result set into the tuplestore */
ExecutorRun(queryDesc, ForwardScanDirection, 0L);
(*queryDesc->dest->rDestroy) (queryDesc->dest);
queryDesc->dest = NULL;
/*
* Now shut down the inner executor.
*/
portal->queryDesc = NULL; /* prevent double shutdown */
ExecutorEnd(queryDesc);
/*
* Reset the position in the result set: ideally, this could be
* implemented by just skipping straight to the tuple # that we need
* to be at, but the tuplestore API doesn't support that. So we start
* at the beginning of the tuplestore and iterate through it until we
* reach where we need to be. FIXME someday?
*/
MemoryContextSwitchTo(portal->holdContext);
if (!portal->atEnd)
PG_TRY();
{
long store_pos;
ActivePortal = portal;
CurrentResourceOwner = portal->resowner;
PortalContext = PortalGetHeapMemory(portal);
QueryContext = portal->queryContext;
if (portal->posOverflow) /* oops, cannot trust portalPos */
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not reposition held cursor")));
MemoryContextSwitchTo(PortalContext);
tuplestore_rescan(portal->holdStore);
/*
* Rewind the executor: we need to store the entire result set in the
* tuplestore, so that subsequent backward FETCHs can be processed.
*/
ExecutorRewind(queryDesc);
for (store_pos = 0; store_pos < portal->portalPos; store_pos++)
/* Change the destination to output to the tuplestore */
queryDesc->dest = CreateDestReceiver(Tuplestore, portal);
/* Fetch the result set into the tuplestore */
ExecutorRun(queryDesc, ForwardScanDirection, 0L);
(*queryDesc->dest->rDestroy) (queryDesc->dest);
queryDesc->dest = NULL;
/*
* Now shut down the inner executor.
*/
portal->queryDesc = NULL; /* prevent double shutdown */
ExecutorEnd(queryDesc);
/*
* Reset the position in the result set: ideally, this could be
* implemented by just skipping straight to the tuple # that we need
* to be at, but the tuplestore API doesn't support that. So we start
* at the beginning of the tuplestore and iterate through it until we
* reach where we need to be. FIXME someday?
*/
MemoryContextSwitchTo(portal->holdContext);
if (!portal->atEnd)
{
HeapTuple tup;
bool should_free;
long store_pos;
tup = tuplestore_gettuple(portal->holdStore, true,
&should_free);
if (portal->posOverflow) /* oops, cannot trust portalPos */
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not reposition held cursor")));
if (tup == NULL)
elog(ERROR, "unexpected end of tuple stream");
tuplestore_rescan(portal->holdStore);
if (should_free)
pfree(tup);
for (store_pos = 0; store_pos < portal->portalPos; store_pos++)
{
HeapTuple tup;
bool should_free;
tup = tuplestore_gettuple(portal->holdStore, true,
&should_free);
if (tup == NULL)
elog(ERROR, "unexpected end of tuple stream");
if (should_free)
pfree(tup);
}
}
}
PG_CATCH();
{
/* Uncaught error while executing portal: mark it dead */
portal->status = PORTAL_FAILED;
/* Restore global vars and propagate error */
ActivePortal = saveActivePortal;
CurrentResourceOwner = saveResourceOwner;
PortalContext = savePortalContext;
QueryContext = saveQueryContext;
PG_RE_THROW();
}
PG_END_TRY();
MemoryContextSwitchTo(oldcxt);
/*
* We can now release any subsidiary memory of the portal's heap
* context; we'll never use it again. The executor already dropped
* its context, but this will clean up anything that glommed onto the
* portal's heap via PortalContext.
*/
MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
/* Mark portal not active */
portal->status = PORTAL_READY;
@ -404,4 +423,12 @@ PersistHoldablePortal(Portal portal)
CurrentResourceOwner = saveResourceOwner;
PortalContext = savePortalContext;
QueryContext = saveQueryContext;
/*
* We can now release any subsidiary memory of the portal's heap
* context; we'll never use it again. The executor already dropped
* its context, but this will clean up anything that glommed onto the
* portal's heap via PortalContext.
*/
MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
}