*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.126 1999/11/25 00:15:57 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.127 1999/11/28 02:10:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "access/genam.h"
#include "access/heapam.h"
+#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/index.h"
#include "parser/parse_oper.h"
#include "storage/sinval.h"
#include "storage/smgr.h"
+#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/inval.h"
#include "utils/portal.h"
#include <sys/resource.h>
#endif
- /* #include <port-protos.h> *//* Why? */
bool VacuumRunning = false;
static void vc_attrstats(Relation onerel, VRelStats *vacrelstats, HeapTuple tuple);
static void vc_bucketcpy(Form_pg_attribute attr, Datum value, Datum *bucket, int *bucket_len);
static void vc_updstats(Oid relid, int num_pages, int num_tuples, bool hasindex, VRelStats *vacrelstats);
-static void vc_delhilowstats(Oid relid, int attcnt, int *attnums);
+static void vc_delstats(Oid relid, int attcnt, int *attnums);
static VPageDescr vc_tidreapped(ItemPointer itemptr, VPageList vpl);
static void vc_reappage(VPageList vpl, VPageDescr vpc);
static void vc_vpinsert(VPageList vpl, VPageDescr vpnew);
-static void vc_free(VRelList vrl);
static void vc_getindices(Oid relid, int *nindices, Relation **Irel);
static void vc_clsindices(int nindices, Relation *Irel);
static void vc_mkindesc(Relation onerel, int nindices, Relation *Irel, IndDesc **Idesc);
void
vacuum(char *vacrel, bool verbose, bool analyze, List *va_spec)
{
- char *pname;
- MemoryContext old;
- PortalVariableMemory pmem;
NameData VacRel;
+ PortalVariableMemory pmem;
+ MemoryContext old;
List *le;
List *va_cols = NIL;
+ if (va_spec != NIL && !analyze)
+ elog(ERROR, "Can't vacuum columns, only tables. You can 'vacuum analyze' columns.");
+
/*
- * Create a portal for safe memory across transctions. We need to
- * palloc the name space for it because our hash function expects the
- * name to be on a longword boundary. CreatePortal copies the name to
- * safe storage for us.
+ * We cannot run VACUUM inside a user transaction block; if we were
+ * inside a transaction, then our commit- and start-transaction-command
+ * calls would not have the intended effect! Furthermore, the forced
+ * commit that occurs before truncating the relation's file would have
+ * the effect of committing the rest of the user's transaction too,
+ * which would certainly not be the desired behavior.
*/
- pname = (char *) palloc(strlen(VACPNAME) + 1);
- strcpy(pname, VACPNAME);
- vc_portal = CreatePortal(pname);
- pfree(pname);
+ if (IsTransactionBlock())
+ elog(ERROR, "VACUUM cannot run inside a BEGIN/END block");
+
+ /* initialize vacuum cleaner, particularly vc_portal */
+ vc_init();
if (verbose)
MESSAGE_LEVEL = NOTICE;
else
MESSAGE_LEVEL = DEBUG;
- /* vacrel gets de-allocated on transaction commit */
+ /* vacrel gets de-allocated on transaction commit, so copy it */
if (vacrel)
strcpy(NameStr(VacRel), vacrel);
+ /* must also copy the column list, if any, to safe storage */
pmem = PortalGetVariableMemory(vc_portal);
old = MemoryContextSwitchTo((MemoryContext) pmem);
-
- if (va_spec != NIL && !analyze)
- elog(ERROR, "Can't vacuum columns, only tables. You can 'vacuum analyze' columns.");
-
foreach(le, va_spec)
{
char *col = (char *) lfirst(le);
- char *dest;
- dest = (char *) palloc(strlen(col) + 1);
- strcpy(dest, col);
- va_cols = lappend(va_cols, dest);
+ va_cols = lappend(va_cols, pstrdup(col));
}
MemoryContextSwitchTo(old);
- /* initialize vacuum cleaner */
- vc_init();
-
/* vacuum the database */
if (vacrel)
vc_vacuum(&VacRel, analyze, va_cols);
else
vc_vacuum(NULL, analyze, NIL);
- PortalDestroy(&vc_portal);
-
/* clean up */
vc_shutdown();
}
/*
* vc_init(), vc_shutdown() -- start up and shut down the vacuum cleaner.
*
- * We run exactly one vacuum cleaner at a time. We use the file system
- * to guarantee an exclusive lock on vacuuming, since a single vacuum
- * cleaner instantiation crosses transaction boundaries, and we'd lose
- * postgres-style locks at the end of every transaction.
+ * Formerly, there was code here to prevent more than one VACUUM from
+ * executing concurrently in the same database. However, there's no
+ * good reason to prevent that, and manually removing lockfiles after
+ * a vacuum crash was a pain for dbadmins. So, forget about lockfiles,
+ * and just rely on the exclusive lock we grab on each target table
+ * to ensure that there aren't two VACUUMs running on the same table
+ * at the same time.
*
* The strangeness with committing and starting transactions in the
* init and shutdown routines is due to the fact that the vacuum cleaner
- * is invoked via a sql command, and so is already executing inside
+ * is invoked via an SQL command, and so is already executing inside
* a transaction. We need to leave ourselves in a predictable state
* on entry and exit to the vacuum cleaner. We commit the transaction
* started in PostgresMain() inside vc_init(), and start one in
static void
vc_init()
{
- int fd;
+ char *pname;
-#ifndef __CYGWIN32__
- if ((fd = open("pg_vlock", O_CREAT | O_EXCL, 0600)) < 0)
-#else
- if ((fd = open("pg_vlock", O_CREAT | O_EXCL | O_BINARY, 0600)) < 0)
-#endif
- {
- elog(ERROR, "Can't create lock file. Is another vacuum cleaner running?\n\
-\tIf not, you may remove the pg_vlock file in the %s\n\
-\tdirectory", DatabasePath);
- }
- close(fd);
+ /*
+ * Create a portal for safe memory across transactions. We need to
+ * palloc the name space for it because our hash function expects the
+ * name to be on a longword boundary. CreatePortal copies the name to
+ * safe storage for us.
+ */
+ pname = pstrdup(VACPNAME);
+ vc_portal = CreatePortal(pname);
+ pfree(pname);
/*
- * By here, exclusive open on the lock file succeeded. If we abort
- * for any reason during vacuuming, we need to remove the lock file.
+ * Set flag to indicate that vc_portal must be removed after an error.
* This global variable is checked in the transaction manager on xact
* abort, and the routine vc_abort() is called if necessary.
*/
-
VacuumRunning = true;
/* matches the StartTransaction in PostgresMain() */
*/
unlink(RELCACHE_INIT_FILENAME);
- /* remove the vacuum cleaner lock file */
- if (unlink("pg_vlock") < 0)
- elog(ERROR, "vacuum: can't destroy lock file!");
+ /*
+ * Release our portal for cross-transaction memory.
+ */
+ PortalDestroy(&vc_portal);
/* okay, we're done */
VacuumRunning = false;
/* matches the CommitTransaction in PostgresMain() */
StartTransactionCommand();
-
}
void
vc_abort()
{
- /* on abort, remove the vacuum cleaner lock file */
- unlink("pg_vlock");
-
+ /* Clear flag first, to avoid recursion if PortalDestroy elog's */
VacuumRunning = false;
+
+ /*
+ * Release our portal for cross-transaction memory.
+ */
+ PortalDestroy(&vc_portal);
}
/*
/* get list of relations */
vrl = vc_getrels(VacRelP);
- if (analyze && VacRelP == NULL && vrl != NULL)
- vc_delhilowstats(InvalidOid, 0, NULL);
-
/* vacuum each heap relation */
for (cur = vrl; cur != (VRelList) NULL; cur = cur->vrl_next)
vc_vacone(cur->vrl_relid, analyze, va_cols);
-
- vc_free(vrl);
}
static VRelList
StartTransactionCommand();
+ /*
+ * Check for user-requested abort. Note we want this to be inside
+ * a transaction, so xact.c doesn't issue useless NOTICE.
+ */
+ if (QueryCancel)
+ CancelQuery();
+
/*
* Race condition -- if the pg_class tuple has gone away since the
* last time we saw it, we don't need to vacuum it.
stats->outfunc = InvalidOid;
}
vacrelstats->va_natts = attr_cnt;
- vc_delhilowstats(relid, ((attnums) ? attr_cnt : 0), attnums);
+ /* delete existing pg_statistics rows for relation */
+ vc_delstats(relid, ((attnums) ? attr_cnt : 0), attnums);
if (attnums)
pfree(attnums);
}
CatalogIndexInsert(irelations, Num_pg_statistic_indices, sd, stup);
CatalogCloseIndices(Num_pg_statistic_indices, irelations);
}
-
+
/* release allocated space */
pfree(DatumGetPointer(values[Anum_pg_statistic_stacommonval-1]));
pfree(DatumGetPointer(values[Anum_pg_statistic_staloval-1]));
}
/*
- * vc_delhilowstats() -- delete pg_statistics rows
+ * vc_delstats() -- delete pg_statistics rows for a relation
*
+ * If a list of attribute numbers is given, only zap stats for those attrs.
*/
static void
-vc_delhilowstats(Oid relid, int attcnt, int *attnums)
+vc_delstats(Oid relid, int attcnt, int *attnums)
{
Relation pgstatistic;
HeapScanDesc scan;
pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock);
- if (relid != InvalidOid)
- {
- ScanKeyEntryInitialize(&key, 0x0, Anum_pg_statistic_starelid,
- F_OIDEQ,
- ObjectIdGetDatum(relid));
- scan = heap_beginscan(pgstatistic, false, SnapshotNow, 1, &key);
- }
- else
- scan = heap_beginscan(pgstatistic, false, SnapshotNow, 0, NULL);
+ ScanKeyEntryInitialize(&key, 0x0, Anum_pg_statistic_starelid,
+ F_OIDEQ, ObjectIdGetDatum(relid));
+ scan = heap_beginscan(pgstatistic, false, SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
{
}
-static void
-vc_free(VRelList vrl)
-{
- VRelList p_vrl;
- MemoryContext old;
- PortalVariableMemory pmem;
-
- pmem = PortalGetVariableMemory(vc_portal);
- old = MemoryContextSwitchTo((MemoryContext) pmem);
-
- while (vrl != (VRelList) NULL)
- {
-
- /* free rel list entry */
- p_vrl = vrl;
- vrl = vrl->vrl_next;
- pfree(p_vrl);
- }
-
- MemoryContextSwitchTo(old);
-}
-
static void *
vc_find_eq(void *bot, int nelem, int size, void *elm,
int (*compar) (const void *, const void *))
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