/*
*--------------------------------------------------------------
* Async_UnlistenOnExit
*
* Clean up the pg_listener table at backend exit.
*
* This is executed if we have done any LISTENs in this backend.
* It might not be necessary anymore, if the user UNLISTENed everything,
* but we don't try to detect that case.
*
* Results:
* XXX
*
* Side effects:
* pg_listener is updated if necessary.
*
*--------------------------------------------------------------
*/
static void
Async_UnlistenOnExit(int code, Datum arg)
{
/*
* We need to start/commit a transaction for the unlisten, but if there is
* already an active transaction we had better abort that one first.
* Otherwise we'd end up committing changes that probably ought to be
* discarded.
*/
AbortOutOfAnyTransaction();
/* Now we can do the unlisten */
StartTransactionCommand();
Async_UnlistenAll();
CommitTransactionCommand();
}
/*
* Async_Unlisten
*
* This is executed by the SQL unlisten command.
*/
void
Async_Unlisten(const char *relname)
{
/* Handle specially the `unlisten "*"' command */
if ((!relname) || (*relname == '\0') || (strcmp(relname, "*") == 0))
{
Async_UnlistenAll();
}
else
{
if (Trace_notify)
elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, MyProcPid);
queue_listen(LISTEN_UNLISTEN, relname);
}
}
/*
*--------------------------------------------------------------
* Async_Unlisten
*
* This is executed by the SQL unlisten command.
*
* Remove the current backend from the list of listening backends
* for the specified relation.
*
* Side effects:
* pg_listener is updated.
*
*--------------------------------------------------------------
*/
void
Async_Unlisten(const char *relname)
{
Relation lRel;
HeapScanDesc scan;
HeapTuple tuple;
/* Handle specially the `unlisten "*"' command */
if ((!relname) || (*relname == '\0') || (strcmp(relname, "*") == 0))
{
Async_UnlistenAll();
return;
}
if (Trace_notify)
elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, MyProcPid);
lRel = heap_open(ListenerRelationId, ExclusiveLock);
scan = heap_beginscan(lRel, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);
if (listener->listenerpid == MyProcPid &&
strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)
{
/* Found the matching tuple, delete it */
simple_heap_delete(lRel, &tuple->t_self);
/*
* We assume there can be only one match, so no need to scan the
* rest of the table
*/
break;
}
}
heap_endscan(scan);
heap_close(lRel, ExclusiveLock);
/*
* We do not complain about unlistening something not being listened;
* should we?
*/
}
static void
DiscardAll(bool isTopLevel)
{
/*
* Disallow DISCARD ALL in a transaction block. This is arguably
* inconsistent (we don't make a similar check in the command sequence
* that DISCARD ALL is equivalent to), but the idea is to catch mistakes:
* DISCARD ALL inside a transaction block would leave the transaction
* still uncommitted.
*/
PreventTransactionChain(isTopLevel, "DISCARD ALL");
SetPGVariable("session_authorization", NIL, false);
ResetAllOptions();
DropAllPreparedStatements();
PortalHashTableDeleteAll();
Async_UnlistenAll();
LockReleaseAll(USER_LOCKMETHOD, true);
ResetPlanCache();
ResetTempTableNamespace();
}
