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/*
* misc_utils.c --
*
* This file defines miscellaneous PostgreSQL utility functions.
*
* Copyright (C) 1999, Massimo Dal Zotto <dz@cs.unitn.it>
*
* This file is distributed under the GNU General Public License
* either version 2, or (at your option) any later version.
*/
#include "postgres.h"
#include <unistd.h>
#include <signal.h>
#include "access/heapam.h"
#include "access/htup.h"
#include "access/relscan.h"
#include "access/skey.h"
#include "access/tupdesc.h"
#include "catalog/catname.h"
#include "catalog/pg_listener.h"
#include "commands/async.h"
#include "fmgr.h"
#include "storage/lmgr.h"
#include "utils/fmgroids.h"
#include "utils/rel.h"
#include "utils/tqual.h"
#include "misc_utils.h"
int
backend_pid(void)
{
return getpid();
}
int
unlisten(char *relname)
{
Async_Unlisten(relname, getpid());
return 0;
}
int
int4max(int x, int y)
{
return Max(x, y);
}
int
int4min(int x, int y)
{
return Min(x, y);
}
/*
* Return the number of active listeners on a relation name.
*/
int
active_listeners(text *relname)
{
HeapTuple lTuple;
Relation lRel;
HeapScanDesc sRel;
TupleDesc tdesc;
ScanKeyData key;
Datum d;
bool isnull;
int len,
pid;
int count = 0;
int ourpid = getpid();
char listen_name[NAMEDATALEN];
lRel = heap_openr(ListenerRelationName, AccessShareLock);
tdesc = RelationGetDescr(lRel);
if (relname && (VARSIZE(relname) > VARHDRSZ))
{
MemSet(listen_name, 0, NAMEDATALEN);
len = Min(VARSIZE(relname) - VARHDRSZ, NAMEDATALEN - 1);
memcpy(listen_name, VARDATA(relname), len);
ScanKeyInit(&key,
Anum_pg_listener_relname,
BTEqualStrategyNumber, F_NAMEEQ,
PointerGetDatum(listen_name));
sRel = heap_beginscan(lRel, SnapshotNow, 1, &key);
}
else
sRel = heap_beginscan(lRel, SnapshotNow, 0, (ScanKey) NULL);
while ((lTuple = heap_getnext(sRel, ForwardScanDirection)) != NULL)
{
d = heap_getattr(lTuple, Anum_pg_listener_pid, tdesc, &isnull);
pid = DatumGetInt32(d);
if ((pid == ourpid) || (kill(pid, 0) == 0))
count++;
}
heap_endscan(sRel);
heap_close(lRel, AccessShareLock);
return count;
}
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