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  • Committer: alvherre
  • Date: 2005-12-16 21:24:52 UTC
  • Revision ID: svn-v4:db760fc0-0f08-0410-9d63-cc6633f64896:trunk:1
Initial import of the REL8_0_3 sources from the Pgsql CVS repository.

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