database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00
Code Activity

Don't reset pg_class.reltuples and relpages in VACUUM, if any pages were

Browse Source 
skipped. We could update relpages anyway, but it seems better to only
update it together with reltuples, because we use the reltuples/relpages
ratio in the planner. Also don't update n_live_tuples in pgstat.

ANALYZE in VACUUM ANALYZE now needs to update pg_class, if the
VACUUM-phase didn't do so. Added some boolean-passing to let analyze_rel
know if it should update pg_class or not.

I also moved the relcache invalidation (to update rd_targblock) from
vac_update_relstats to where RelationTruncate is called, because
vac_update_relstats is not called for partial vacuums anymore. It's more
obvious to send the invalidation close to the truncation that requires it.

Per report by Ned T. Crigler.
This commit is contained in:
Heikki Linnakangas
2008-12-17 09:15:03 +00:00
parent 5a90bc1fbe
commit dcf8409985
7 changed files with 94 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
src/backend/commands/vacuumlazy.c
View File

@ -29,7 +29,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.113 2008/12/04 11:42:23 heikki Exp $
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.114 2008/12/17 09:15:02 heikki Exp $
*
*-------------------------------------------------------------------------
*/
@ -50,6 +50,7 @@
#include "storage/bufmgr.h"
#include "storage/freespace.h"
#include "storage/lmgr.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/pg_rusage.h"
@ -135,7 +136,7 @@ static int vac_cmp_itemptr(const void *left, const void *right);
*/
void
lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
BufferAccessStrategy bstrategy)
BufferAccessStrategy bstrategy, bool *scanned_all)
{
LVRelStats *vacrelstats;
Relation *Irel;
@ -163,7 +164,7 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
vacrelstats->num_index_scans = 0;
vacrelstats->scanned_all = true;
vacrelstats->scanned_all = true; /* will be cleared if we skip a page */
/* Open all indexes of the relation */
vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel);
@ -190,16 +191,23 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
FreeSpaceMapVacuum(onerel);
/*
* Update statistics in pg_class. We can only advance relfrozenxid if we
* didn't skip any pages.
* Update statistics in pg_class. But only if we didn't skip any pages;
* the tuple count only includes tuples from the pages we've visited, and
* we haven't frozen tuples in unvisited pages either. The page count is
* accurate in any case, but because we use the reltuples / relpages
* ratio in the planner, it's better to not update relpages either if we
* can't update reltuples.
*/
vac_update_relstats(onerel,
vacrelstats->rel_pages, vacrelstats->rel_tuples,
vacrelstats->hasindex,
vacrelstats->scanned_all ? FreezeLimit : InvalidOid);
if (vacrelstats->scanned_all)
vac_update_relstats(onerel,
vacrelstats->rel_pages, vacrelstats->rel_tuples,
vacrelstats->hasindex,
FreezeLimit);
/* report results to the stats collector, too */
pgstat_report_vacuum(RelationGetRelid(onerel), onerel->rd_rel->relisshared,
pgstat_report_vacuum(RelationGetRelid(onerel),
onerel->rd_rel->relisshared,
vacrelstats->scanned_all,
vacstmt->analyze, vacrelstats->rel_tuples);
/* and log the action if appropriate */
@ -221,6 +229,9 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
vacrelstats->tuples_deleted, vacrelstats->rel_tuples,
pg_rusage_show(&ru0))));
}
if (scanned_all)
*scanned_all = vacrelstats->scanned_all;
}
@ -952,12 +963,14 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
*/
RelationTruncate(onerel, new_rel_pages);
/* force relcache inval so all backends reset their rd_targblock */
CacheInvalidateRelcache(onerel);
/*
* Note: once we have truncated, we *must* keep the exclusive lock until
* commit. The sinval message that will be sent at commit (as a result of
* vac_update_relstats()) must be received by other backends, to cause
* them to reset their rd_targblock values, before they can safely access
* the table again.
* commit. The sinval message won't be sent until commit, and other
* backends must see it and reset their rd_targblock values before they
* can safely access the table again.
*/
/* update statistics */