postgresql/contrib/miscutil/misc_utils.c
Tom Lane 44fbe20d62 Restructure indexscan API (index_beginscan, index_getnext) per
yesterday's proposal to pghackers.  Also remove unnecessary parameters
to heap_beginscan, heap_rescan.  I modified pg_proc.h to reflect the
new numbers of parameters for the AM interface routines, but did not
force an initdb because nothing actually looks at those fields.
2002-05-20 23:51:44 +00:00

114 lines
2.2 KiB
C

/*
* 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 <string.h>
#include <errno.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/palloc.h"
#include "utils/rel.h"
#include "utils/tqual.h"
#include "misc_utils.h"
#undef MIN
#define MIN(x,y) ((x)<=(y) ? (x) : (y))
int
backend_pid()
{
return getpid();
}
int
unlisten(char *relname)
{
Async_Unlisten(relname, getpid());
return 0;
}
int
max(int x, int y)
{
return ((x > y) ? x : y);
}
int
min(int x, int y)
{
return ((x < y) ? 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);
ScanKeyEntryInitialize(&key, 0,
Anum_pg_listener_relname,
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, SIGTSTP) == 0))
count++;
}
heap_endscan(sRel);
heap_close(lRel, AccessShareLock);
return count;
}