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Commitdcf8409

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committed
Don't reset pg_class.reltuples and relpages in VACUUM, if any pages were
skipped. We could update relpages anyway, but it seems better to onlyupdate it together with reltuples, because we use the reltuples/relpagesratio in the planner. Also don't update n_live_tuples in pgstat.ANALYZE in VACUUM ANALYZE now needs to update pg_class, if theVACUUM-phase didn't do so. Added some boolean-passing to let analyze_relknow if it should update pg_class or not.I also moved the relcache invalidation (to update rd_targblock) fromvac_update_relstats to where RelationTruncate is called, becausevac_update_relstats is not called for partial vacuums anymore. It's moreobvious to send the invalidation close to the truncation that requires it.Per report by Ned T. Crigler.
1 parent5a90bc1 commitdcf8409

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7 files changed

+94
-61
lines changed

7 files changed

+94
-61
lines changed

‎src/backend/commands/analyze.c‎

Lines changed: 23 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.129 2008/12/13 19:13:44 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.130 2008/12/17 09:15:02 heikki Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -101,10 +101,18 @@ static bool std_typanalyze(VacAttrStats *stats);
101101

102102
/*
103103
*analyze_rel() -- analyze one relation
104+
*
105+
* If update_reltuples is true, we update reltuples and relpages columns
106+
* in pg_class. Caller should pass false if we're part of VACUUM ANALYZE,
107+
* and the VACUUM didn't skip any pages. We only have an approximate count,
108+
* so we don't want to overwrite the accurate values already inserted by the
109+
* VACUUM in that case. VACUUM always scans all indexes, however, so the
110+
* pg_class entries for indexes are never updated if we're part of VACUUM
111+
* ANALYZE.
104112
*/
105113
void
106114
analyze_rel(Oidrelid,VacuumStmt*vacstmt,
107-
BufferAccessStrategybstrategy)
115+
BufferAccessStrategybstrategy,boolupdate_reltuples)
108116
{
109117
Relationonerel;
110118
intattr_cnt,
@@ -364,7 +372,7 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
364372
* autovacuum code doesn't go nuts trying to get stats about a
365373
* zero-column table.
366374
*/
367-
if (!vacstmt->vacuum)
375+
if (update_reltuples)
368376
pgstat_report_analyze(onerel,0,0);
369377
gotocleanup;
370378
}
@@ -455,18 +463,24 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
455463
}
456464

457465
/*
458-
* If we are running a standalone ANALYZE, update pages/tuples stats in
459-
* pg_class. We know the accurate page count from the smgr, but only an
460-
* approximate number of tuples; therefore, if we are part of VACUUM
461-
* ANALYZE do *not* overwrite the accurate count already inserted by
462-
* VACUUM.The same consideration applies to indexes.
466+
* Update pages/tuples stats in pg_class.
463467
*/
464-
if (!vacstmt->vacuum)
468+
if (update_reltuples)
465469
{
466470
vac_update_relstats(onerel,
467471
RelationGetNumberOfBlocks(onerel),
468472
totalrows,hasindex,InvalidTransactionId);
473+
/* report results to the stats collector, too */
474+
pgstat_report_analyze(onerel,totalrows,totaldeadrows);
475+
}
469476

477+
/*
478+
* Same for indexes. Vacuum always scans all indexes, so if we're part of
479+
* VACUUM ANALYZE, don't overwrite the accurate count already inserted by
480+
* VACUUM.
481+
*/
482+
if (!vacstmt->vacuum)
483+
{
470484
for (ind=0;ind<nindexes;ind++)
471485
{
472486
AnlIndexData*thisdata=&indexdata[ind];
@@ -477,9 +491,6 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
477491
RelationGetNumberOfBlocks(Irel[ind]),
478492
totalindexrows, false,InvalidTransactionId);
479493
}
480-
481-
/* report results to the stats collector, too */
482-
pgstat_report_analyze(onerel,totalrows,totaldeadrows);
483494
}
484495

485496
/* We skip to here if there were no analyzable columns */

‎src/backend/commands/vacuum.c‎

Lines changed: 26 additions & 21 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
*
1414
*
1515
* IDENTIFICATION
16-
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.382 2008/12/03 13:05:22 heikki Exp $
16+
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.383 2008/12/17 09:15:02 heikki Exp $
1717
*
1818
*-------------------------------------------------------------------------
1919
*/
@@ -216,7 +216,7 @@ static List *get_rel_oids(Oid relid, const RangeVar *vacrel,
216216
constchar*stmttype);
217217
staticvoidvac_truncate_clog(TransactionIdfrozenXID);
218218
staticvoidvacuum_rel(Oidrelid,VacuumStmt*vacstmt,booldo_toast,
219-
boolfor_wraparound);
219+
boolfor_wraparound,bool*scanned_all);
220220
staticvoidfull_vacuum_rel(Relationonerel,VacuumStmt*vacstmt);
221221
staticvoidscan_heap(VRelStats*vacrelstats,Relationonerel,
222222
VacPageListvacuum_pages,VacPageListfraged_pages);
@@ -436,9 +436,11 @@ vacuum(VacuumStmt *vacstmt, Oid relid, bool do_toast,
436436
foreach(cur,relations)
437437
{
438438
Oidrelid=lfirst_oid(cur);
439+
boolscanned_all= false;
439440

440441
if (vacstmt->vacuum)
441-
vacuum_rel(relid,vacstmt,do_toast,for_wraparound);
442+
vacuum_rel(relid,vacstmt,do_toast,for_wraparound,
443+
&scanned_all);
442444

443445
if (vacstmt->analyze)
444446
{
@@ -460,7 +462,7 @@ vacuum(VacuumStmt *vacstmt, Oid relid, bool do_toast,
460462
else
461463
old_context=MemoryContextSwitchTo(anl_context);
462464

463-
analyze_rel(relid,vacstmt,vac_strategy);
465+
analyze_rel(relid,vacstmt,vac_strategy, !scanned_all);
464466

465467
if (use_own_xacts)
466468
{
@@ -756,21 +758,9 @@ vac_update_relstats(Relation relation,
756758
dirty= true;
757759
}
758760

759-
/*
760-
* If anything changed, write out the tuple. Even if nothing changed,
761-
* force relcache invalidation so all backends reset their rd_targblock
762-
* --- otherwise it might point to a page we truncated away.
763-
*/
761+
/* If anything changed, write out the tuple. */
764762
if (dirty)
765-
{
766763
heap_inplace_update(rd,ctup);
767-
/* the above sends a cache inval message */
768-
}
769-
else
770-
{
771-
/* no need to change tuple, but force relcache inval anyway */
772-
CacheInvalidateRelcacheByTuple(ctup);
773-
}
774764

775765
heap_close(rd,RowExclusiveLock);
776766
}
@@ -986,10 +976,14 @@ vac_truncate_clog(TransactionId frozenXID)
986976
*many small transactions. Otherwise, two-phase locking would require
987977
*us to lock the entire database during one pass of the vacuum cleaner.
988978
*
979+
*We'll return true in *scanned_all if the vacuum scanned all heap
980+
*pages, and updated pg_class.
981+
*
989982
*At entry and exit, we are not inside a transaction.
990983
*/
991984
staticvoid
992-
vacuum_rel(Oidrelid,VacuumStmt*vacstmt,booldo_toast,boolfor_wraparound)
985+
vacuum_rel(Oidrelid,VacuumStmt*vacstmt,booldo_toast,boolfor_wraparound,
986+
bool*scanned_all)
993987
{
994988
LOCKMODElmode;
995989
Relationonerel;
@@ -998,6 +992,9 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound)
998992
Oidsave_userid;
999993
boolsave_secdefcxt;
1000994

995+
if (scanned_all)
996+
*scanned_all= false;
997+
1001998
/* Begin a transaction for vacuuming this relation */
1002999
StartTransactionCommand();
10031000

@@ -1162,7 +1159,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound)
11621159
if (vacstmt->full)
11631160
full_vacuum_rel(onerel,vacstmt);
11641161
else
1165-
lazy_vacuum_rel(onerel,vacstmt,vac_strategy);
1162+
lazy_vacuum_rel(onerel,vacstmt,vac_strategy,scanned_all);
11661163

11671164
/* Restore userid */
11681165
SetUserIdAndContext(save_userid,save_secdefcxt);
@@ -1184,7 +1181,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound)
11841181
* totally unimportant for toast relations.
11851182
*/
11861183
if (toast_relid!=InvalidOid)
1187-
vacuum_rel(toast_relid,vacstmt, false,for_wraparound);
1184+
vacuum_rel(toast_relid,vacstmt, false,for_wraparound,NULL);
11881185

11891186
/*
11901187
* Now release the session-level lock on the master table.
@@ -1296,7 +1293,7 @@ full_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
12961293

12971294
/* report results to the stats collector, too */
12981295
pgstat_report_vacuum(RelationGetRelid(onerel),onerel->rd_rel->relisshared,
1299-
vacstmt->analyze,vacrelstats->rel_tuples);
1296+
true,vacstmt->analyze,vacrelstats->rel_tuples);
13001297
}
13011298

13021299

@@ -2866,6 +2863,10 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
28662863
if (blkno<nblocks)
28672864
{
28682865
RelationTruncate(onerel,blkno);
2866+
2867+
/* force relcache inval so all backends reset their rd_targblock */
2868+
CacheInvalidateRelcache(onerel);
2869+
28692870
vacrelstats->rel_pages=blkno;/* set new number of blocks */
28702871
}
28712872

@@ -3286,6 +3287,10 @@ vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
32863287
RelationGetRelationName(onerel),
32873288
vacrelstats->rel_pages,relblocks)));
32883289
RelationTruncate(onerel,relblocks);
3290+
3291+
/* force relcache inval so all backends reset their rd_targblock */
3292+
CacheInvalidateRelcache(onerel);
3293+
32893294
vacrelstats->rel_pages=relblocks;/* set new number of blocks */
32903295
}
32913296
}

‎src/backend/commands/vacuumlazy.c‎

Lines changed: 27 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -29,7 +29,7 @@
2929
*
3030
*
3131
* IDENTIFICATION
32-
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.113 2008/12/04 11:42:23 heikki Exp $
32+
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.114 2008/12/17 09:15:02 heikki Exp $
3333
*
3434
*-------------------------------------------------------------------------
3535
*/
@@ -50,6 +50,7 @@
5050
#include"storage/bufmgr.h"
5151
#include"storage/freespace.h"
5252
#include"storage/lmgr.h"
53+
#include"utils/inval.h"
5354
#include"utils/lsyscache.h"
5455
#include"utils/memutils.h"
5556
#include"utils/pg_rusage.h"
@@ -135,7 +136,7 @@ static intvac_cmp_itemptr(const void *left, const void *right);
135136
*/
136137
void
137138
lazy_vacuum_rel(Relationonerel,VacuumStmt*vacstmt,
138-
BufferAccessStrategybstrategy)
139+
BufferAccessStrategybstrategy,bool*scanned_all)
139140
{
140141
LVRelStats*vacrelstats;
141142
Relation*Irel;
@@ -163,7 +164,7 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
163164
vacrelstats= (LVRelStats*)palloc0(sizeof(LVRelStats));
164165

165166
vacrelstats->num_index_scans=0;
166-
vacrelstats->scanned_all= true;
167+
vacrelstats->scanned_all= true;/* will be cleared if we skip a page */
167168

168169
/* Open all indexes of the relation */
169170
vac_open_indexes(onerel,RowExclusiveLock,&nindexes,&Irel);
@@ -190,16 +191,23 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
190191
FreeSpaceMapVacuum(onerel);
191192

192193
/*
193-
* Update statistics in pg_class. We can only advance relfrozenxid if we
194-
* didn't skip any pages.
194+
* Update statistics in pg_class. But only if we didn't skip any pages;
195+
* the tuple count only includes tuples from the pages we've visited, and
196+
* we haven't frozen tuples in unvisited pages either. The page count is
197+
* accurate in any case, but because we use the reltuples / relpages
198+
* ratio in the planner, it's better to not update relpages either if we
199+
* can't update reltuples.
195200
*/
196-
vac_update_relstats(onerel,
197-
vacrelstats->rel_pages,vacrelstats->rel_tuples,
198-
vacrelstats->hasindex,
199-
vacrelstats->scanned_all ?FreezeLimit :InvalidOid);
201+
if (vacrelstats->scanned_all)
202+
vac_update_relstats(onerel,
203+
vacrelstats->rel_pages,vacrelstats->rel_tuples,
204+
vacrelstats->hasindex,
205+
FreezeLimit);
200206

201207
/* report results to the stats collector, too */
202-
pgstat_report_vacuum(RelationGetRelid(onerel),onerel->rd_rel->relisshared,
208+
pgstat_report_vacuum(RelationGetRelid(onerel),
209+
onerel->rd_rel->relisshared,
210+
vacrelstats->scanned_all,
203211
vacstmt->analyze,vacrelstats->rel_tuples);
204212

205213
/* and log the action if appropriate */
@@ -221,6 +229,9 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
221229
vacrelstats->tuples_deleted,vacrelstats->rel_tuples,
222230
pg_rusage_show(&ru0))));
223231
}
232+
233+
if (scanned_all)
234+
*scanned_all=vacrelstats->scanned_all;
224235
}
225236

226237

@@ -952,12 +963,14 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
952963
*/
953964
RelationTruncate(onerel,new_rel_pages);
954965

966+
/* force relcache inval so all backends reset their rd_targblock */
967+
CacheInvalidateRelcache(onerel);
968+
955969
/*
956970
* Note: once we have truncated, we *must* keep the exclusive lock until
957-
* commit.The sinval message that will be sent at commit (as a result of
958-
* vac_update_relstats()) must be received by other backends, to cause
959-
* them to reset their rd_targblock values, before they can safely access
960-
* the table again.
971+
* commit.The sinval message won't be sent until commit, and other
972+
* backends must see it and reset their rd_targblock values before they
973+
* can safely access the table again.
961974
*/
962975

963976
/* update statistics */

‎src/backend/parser/gram.y‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.643 2008/12/04 17:51:26 petere Exp $
14+
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.644 2008/12/17 09:15:02 heikki Exp $
1515
*
1616
* HISTORY
1717
* AUTHORDATEMAJOR EVENT
@@ -5875,7 +5875,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose
58755875
n->analyze =false;
58765876
n->full =$2;
58775877
n->freeze_min_age =$3 ?0 : -1;
5878-
n->scan_all =$3;
5878+
n->scan_all =$2 ||$3;
58795879
n->verbose =$4;
58805880
n->relation =NULL;
58815881
n->va_cols = NIL;
@@ -5888,7 +5888,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose
58885888
n->analyze =false;
58895889
n->full =$2;
58905890
n->freeze_min_age =$3 ?0 : -1;
5891-
n->scan_all =$3;
5891+
n->scan_all =$2 ||$3;
58925892
n->verbose =$4;
58935893
n->relation =$5;
58945894
n->va_cols = NIL;
@@ -5900,7 +5900,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose
59005900
n->vacuum =true;
59015901
n->full =$2;
59025902
n->freeze_min_age =$3 ?0 : -1;
5903-
n->scan_all =$3;
5903+
n->scan_all =$2 ||$3;
59045904
n->verbose |=$4;
59055905
$$ = (Node *)n;
59065906
}

‎src/backend/postmaster/pgstat.c‎

Lines changed: 8 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
*
1414
*Copyright (c) 2001-2008, PostgreSQL Global Development Group
1515
*
16-
*$PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.185 2008/12/0815:44:54 tgl Exp $
16+
*$PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.186 2008/12/17 09:15:03 heikki Exp $
1717
* ----------
1818
*/
1919
#include"postgres.h"
@@ -1178,7 +1178,7 @@ pgstat_report_autovac(Oid dboid)
11781178
* ---------
11791179
*/
11801180
void
1181-
pgstat_report_vacuum(Oidtableoid,boolshared,
1181+
pgstat_report_vacuum(Oidtableoid,boolshared,boolscanned_all,
11821182
boolanalyze,PgStat_Countertuples)
11831183
{
11841184
PgStat_MsgVacuummsg;
@@ -1189,6 +1189,7 @@ pgstat_report_vacuum(Oid tableoid, bool shared,
11891189
pgstat_setheader(&msg.m_hdr,PGSTAT_MTYPE_VACUUM);
11901190
msg.m_databaseid=shared ?InvalidOid :MyDatabaseId;
11911191
msg.m_tableoid=tableoid;
1192+
msg.m_scanned_all=scanned_all;
11921193
msg.m_analyze=analyze;
11931194
msg.m_autovacuum=IsAutoVacuumWorkerProcess();/* is this autovacuum? */
11941195
msg.m_vacuumtime=GetCurrentTimestamp();
@@ -3765,12 +3766,14 @@ pgstat_recv_vacuum(PgStat_MsgVacuum *msg, int len)
37653766
tabentry->autovac_vacuum_timestamp=msg->m_vacuumtime;
37663767
else
37673768
tabentry->vacuum_timestamp=msg->m_vacuumtime;
3768-
tabentry->n_live_tuples=msg->m_tuples;
3769+
if (msg->m_scanned_all)
3770+
tabentry->n_live_tuples=msg->m_tuples;
37693771
/* Resetting dead_tuples to 0 is an approximation ... */
37703772
tabentry->n_dead_tuples=0;
37713773
if (msg->m_analyze)
37723774
{
3773-
tabentry->last_anl_tuples=msg->m_tuples;
3775+
if (msg->m_scanned_all)
3776+
tabentry->last_anl_tuples=msg->m_tuples;
37743777
if (msg->m_autovacuum)
37753778
tabentry->autovac_analyze_timestamp=msg->m_vacuumtime;
37763779
else
@@ -3780,7 +3783,7 @@ pgstat_recv_vacuum(PgStat_MsgVacuum *msg, int len)
37803783
{
37813784
/* last_anl_tuples must never exceed n_live_tuples+n_dead_tuples */
37823785
tabentry->last_anl_tuples=Min(tabentry->last_anl_tuples,
3783-
msg->m_tuples);
3786+
tabentry->n_live_tuples);
37843787
}
37853788
}
37863789

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