111 lines
2.1 KiB
C
111 lines
2.1 KiB
C
/*
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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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#undef MIN
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#define MIN(x,y) ((x)<=(y) ? (x) : (y))
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int
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backend_pid()
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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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max(int x, int y)
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{
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return ((x > y) ? x : y);
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}
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int
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min(int x, int y)
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{
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return ((x < y) ? 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, SIGTSTP) == 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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}
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