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bd272cace6
additional argument specifying the kind of lock to acquire/release (or 'NoLock' to do no lock processing). Ensure that all relations are locked with some appropriate lock level before being examined --- this ensures that relevant shared-inval messages have been processed and should prevent problems caused by concurrent VACUUM. Fix several bugs having to do with mismatched increment/decrement of relation ref count and mismatched heap_open/close (which amounts to the same thing). A bogus ref count on a relation doesn't matter much *unless* a SI Inval message happens to arrive at the wrong time, which is probably why we got away with this sloppiness for so long. Repair missing grab of AccessExclusiveLock in DROP TABLE, ALTER/RENAME TABLE, etc, as noted by Hiroshi. Recommend 'make clean all' after pulling this update; I modified the Relation struct layout slightly. Will post further discussion to pghackers list shortly.
147 lines
2.7 KiB
C
147 lines
2.7 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) 1998, 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 <unistd.h>
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#include <signal.h>
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#include <string.h>
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#include <errno.h>
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#include "postgres.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 "storage/lmgr.h"
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#include "utils/fmgr.h"
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#include "utils/palloc.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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#define MIN(x,y) ((x)<=(y) ? (x) : (y))
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extern int ExecutorLimit(int limit);
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extern void Async_Unlisten(char *relname, int pid);
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extern int assertTest(int val);
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#ifdef ASSERT_CHECKING_TEST
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extern int assertEnable(int val);
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#endif
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int
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query_limit(int limit)
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{
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return ExecutorLimit(limit);
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}
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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, 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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len = MIN(VARSIZE(relname)-VARHDRSZ, NAMEDATALEN-1);
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strncpy(listen_name, VARDATA(relname), len);
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listen_name[len] = '\0';
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ScanKeyEntryInitialize(&key, 0,
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Anum_pg_listener_relname,
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F_NAMEEQ,
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PointerGetDatum(listen_name));
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sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, &key);
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} else {
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sRel = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey)NULL);
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}
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while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0)))
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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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/* elog(NOTICE, "%d ok", pid); */
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count++;
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}
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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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int
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assert_enable(int val)
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{
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return assertEnable(val);
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}
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#ifdef ASSERT_CHECKING_TEST
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int
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assert_test(int val)
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{
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return assertTest(val);
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}
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#endif
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/* end of file */
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/*
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* Local Variables:
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* tab-width: 4
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* c-indent-level: 4
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* c-basic-offset: 4
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* End:
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*/
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