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Commit3b0347b

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Move the tuple freezing point in CLUSTER to a point further back in the past,
to avoid losing useful Xid information in not-so-old tuples. This makesCLUSTER behave the same as VACUUM as far a tuple-freezing behavior goes(though CLUSTER does not yet advance the table's relfrozenxid).While at it, move the actual freezing operation in rewriteheap.c to a moreappropriate place, and document it thoroughly. This part of the patch fromTom Lane.
1 parent90cbc63 commit3b0347b

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6 files changed

+44
-21
lines changed

6 files changed

+44
-21
lines changed

‎src/backend/access/heap/rewriteheap.c

Lines changed: 20 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -96,7 +96,7 @@
9696
* Portions Copyright (c) 1994-5, Regents of the University of California
9797
*
9898
* IDENTIFICATION
99-
* $PostgreSQL: pgsql/src/backend/access/heap/rewriteheap.c,v 1.4 2007/05/16 16:36:56 alvherre Exp $
99+
* $PostgreSQL: pgsql/src/backend/access/heap/rewriteheap.c,v 1.5 2007/05/17 15:28:29 alvherre Exp $
100100
*
101101
*-------------------------------------------------------------------------
102102
*/
@@ -123,6 +123,8 @@ typedef struct RewriteStateData
123123
boolrs_use_wal;/* must we WAL-log inserts? */
124124
TransactionIdrs_oldest_xmin;/* oldest xmin used by caller to
125125
* determine tuple visibility */
126+
TransactionIdrs_freeze_xid;/* Xid that will be used as freeze
127+
* cutoff point */
126128
MemoryContextrs_cxt;/* for hash tables and entries and
127129
* tuples in them */
128130
HTAB*rs_unresolved_tups;/* unmatched A tuples */
@@ -171,14 +173,15 @@ static void raw_heap_insert(RewriteState state, HeapTuple tup);
171173
*
172174
* new_heapnew, locked heap relation to insert tuples to
173175
* oldest_xminxid used by the caller to determine which tuples are dead
176+
* freeze_xidxid before which tuples will be frozen
174177
* use_walshould the inserts to the new heap be WAL-logged?
175178
*
176179
* Returns an opaque RewriteState, allocated in current memory context,
177180
* to be used in subsequent calls to the other functions.
178181
*/
179182
RewriteState
180183
begin_heap_rewrite(Relationnew_heap,TransactionIdoldest_xmin,
181-
booluse_wal)
184+
TransactionIdfreeze_xid,booluse_wal)
182185
{
183186
RewriteStatestate;
184187
MemoryContextrw_cxt;
@@ -206,6 +209,7 @@ begin_heap_rewrite(Relation new_heap, TransactionId oldest_xmin,
206209
state->rs_buffer_valid= false;
207210
state->rs_use_wal=use_wal;
208211
state->rs_oldest_xmin=oldest_xmin;
212+
state->rs_freeze_xid=freeze_xid;
209213
state->rs_cxt=rw_cxt;
210214

211215
/* Initialize hash tables used to track update chains */
@@ -292,7 +296,9 @@ end_heap_rewrite(RewriteState state)
292296
/*
293297
* Add a tuple to the new heap.
294298
*
295-
* Visibility information is copied from the original tuple.
299+
* Visibility information is copied from the original tuple, except that
300+
* we "freeze" very-old tuples. Note that since we scribble on new_tuple,
301+
* it had better be temp storage not a pointer to the original tuple.
296302
*
297303
* stateopaque state as returned by begin_heap_rewrite
298304
* old_tupleoriginal tuple in the old heap
@@ -323,6 +329,17 @@ rewrite_heap_tuple(RewriteState state,
323329
new_tuple->t_data->t_infomask |=
324330
old_tuple->t_data->t_infomask&HEAP_XACT_MASK;
325331

332+
/*
333+
* While we have our hands on the tuple, we may as well freeze any
334+
* very-old xmin or xmax, so that future VACUUM effort can be saved.
335+
*
336+
* Note we abuse heap_freeze_tuple() a bit here, since it's expecting
337+
* to be given a pointer to a tuple in a disk buffer. It happens
338+
* though that we can get the right things to happen by passing
339+
* InvalidBuffer for the buffer.
340+
*/
341+
heap_freeze_tuple(new_tuple->t_data,state->rs_freeze_xid,InvalidBuffer);
342+
326343
/*
327344
* Invalid ctid means that ctid should point to the tuple itself.
328345
* We'll override it later if the tuple is part of an update chain.
@@ -538,8 +555,6 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
538555
OffsetNumbernewoff;
539556
HeapTupleheaptup;
540557

541-
heap_freeze_tuple(tup->t_data,state->rs_oldest_xmin,InvalidBuffer);
542-
543558
/*
544559
* If the new tuple is too big for storage or contains already toasted
545560
* out-of-line attributes from some other relation, invoke the toaster.

‎src/backend/commands/cluster.c

Lines changed: 11 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.159 2007/04/08 01:26:28 tgl Exp $
14+
* $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.160 2007/05/17 15:28:29 alvherre Exp $
1515
*
1616
*-------------------------------------------------------------------------
1717
*/
@@ -29,6 +29,7 @@
2929
#include"catalog/namespace.h"
3030
#include"catalog/toasting.h"
3131
#include"commands/cluster.h"
32+
#include"commands/vacuum.h"
3233
#include"miscadmin.h"
3334
#include"storage/procarray.h"
3435
#include"utils/acl.h"
@@ -657,6 +658,7 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
657658
HeapTupletuple;
658659
booluse_wal;
659660
TransactionIdOldestXmin;
661+
TransactionIdFreezeXid;
660662
RewriteStaterwstate;
661663

662664
/*
@@ -688,11 +690,16 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
688690
/* use_wal off requires rd_targblock be initially invalid */
689691
Assert(NewHeap->rd_targblock==InvalidBlockNumber);
690692

691-
/* Get the cutoff xmin we'll use to weed out dead tuples */
692-
OldestXmin=GetOldestXmin(OldHeap->rd_rel->relisshared, true);
693+
/*
694+
* compute xids used to freeze and weed out dead tuples. We use -1
695+
* freeze_min_age to avoid having CLUSTER freeze tuples earlier than
696+
* a plain VACUUM would.
697+
*/
698+
vacuum_set_xid_limits(-1,OldHeap->rd_rel->relisshared,
699+
&OldestXmin,&FreezeXid);
693700

694701
/* Initialize the rewrite operation */
695-
rwstate=begin_heap_rewrite(NewHeap,OldestXmin,use_wal);
702+
rwstate=begin_heap_rewrite(NewHeap,OldestXmin,FreezeXid,use_wal);
696703

697704
/*
698705
* Scan through the OldHeap in OldIndex order and copy each tuple into the

‎src/backend/commands/vacuum.c

Lines changed: 5 additions & 5 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 1.350 2007/04/16 18:29:50 alvherre Exp $
16+
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.351 2007/05/17 15:28:29 alvherre Exp $
1717
*
1818
*-------------------------------------------------------------------------
1919
*/
@@ -566,7 +566,7 @@ get_rel_oids(List *relids, const RangeVar *vacrel, const char *stmttype)
566566
* vacuum_set_xid_limits() -- compute oldest-Xmin and freeze cutoff points
567567
*/
568568
void
569-
vacuum_set_xid_limits(VacuumStmt*vacstmt,boolsharedRel,
569+
vacuum_set_xid_limits(intfreeze_min_age,boolsharedRel,
570570
TransactionId*oldestXmin,
571571
TransactionId*freezeLimit)
572572
{
@@ -588,12 +588,12 @@ vacuum_set_xid_limits(VacuumStmt *vacstmt, bool sharedRel,
588588
Assert(TransactionIdIsNormal(*oldestXmin));
589589

590590
/*
591-
* Determine the minimum freeze age to use: as specifiedin thevacstmt,
591+
* Determine the minimum freeze age to use: as specifiedby thecaller,
592592
* or vacuum_freeze_min_age, but in any case not more than half
593593
* autovacuum_freeze_max_age, so that autovacuums to prevent XID
594594
* wraparound won't occur too frequently.
595595
*/
596-
freezemin=vacstmt->freeze_min_age;
596+
freezemin=freeze_min_age;
597597
if (freezemin<0)
598598
freezemin=vacuum_freeze_min_age;
599599
freezemin=Min(freezemin,autovacuum_freeze_max_age /2);
@@ -1154,7 +1154,7 @@ full_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
11541154
i;
11551155
VRelStats*vacrelstats;
11561156

1157-
vacuum_set_xid_limits(vacstmt,onerel->rd_rel->relisshared,
1157+
vacuum_set_xid_limits(vacstmt->freeze_min_age,onerel->rd_rel->relisshared,
11581158
&OldestXmin,&FreezeLimit);
11591159

11601160
/*

‎src/backend/commands/vacuumlazy.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -36,7 +36,7 @@
3636
*
3737
*
3838
* IDENTIFICATION
39-
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.88 2007/04/30 03:23:48 tgl Exp $
39+
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.89 2007/05/17 15:28:29 alvherre Exp $
4040
*
4141
*-------------------------------------------------------------------------
4242
*/
@@ -158,7 +158,7 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
158158
else
159159
elevel=DEBUG2;
160160

161-
vacuum_set_xid_limits(vacstmt,onerel->rd_rel->relisshared,
161+
vacuum_set_xid_limits(vacstmt->freeze_min_age,onerel->rd_rel->relisshared,
162162
&OldestXmin,&FreezeLimit);
163163

164164
vacrelstats= (LVRelStats*)palloc0(sizeof(LVRelStats));

‎src/include/access/rewriteheap.h

Lines changed: 4 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
77
* Portions Copyright (c) 1994-5, Regents of the University of California
88
*
9-
* $PostgreSQL: pgsql/src/include/access/rewriteheap.h,v 1.1 2007/04/08 01:26:33 tgl Exp $
9+
* $PostgreSQL: pgsql/src/include/access/rewriteheap.h,v 1.2 2007/05/17 15:28:29 alvherre Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -20,10 +20,11 @@
2020
typedefstructRewriteStateData*RewriteState;
2121

2222
externRewriteStatebegin_heap_rewrite(RelationNewHeap,
23-
TransactionIdOldestXmin,booluse_wal);
23+
TransactionIdOldestXmin,TransactionIdFreezeXid,
24+
booluse_wal);
2425
externvoidend_heap_rewrite(RewriteStatestate);
2526
externvoidrewrite_heap_tuple(RewriteStatestate,HeapTupleoldTuple,
26-
HeapTuplenewTuple);
27+
HeapTuplenewTuple);
2728
externvoidrewrite_heap_dead_tuple(RewriteStatestate,HeapTupleoldTuple);
2829

2930
#endif/* REWRITE_HEAP_H */

‎src/include/commands/vacuum.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/include/commands/vacuum.h,v 1.70 2007/03/13 00:33:43 tgl Exp $
10+
* $PostgreSQL: pgsql/src/include/commands/vacuum.h,v 1.71 2007/05/17 15:28:29 alvherre Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -119,7 +119,7 @@ extern void vac_update_relstats(Oid relid,
119119
doublenum_tuples,
120120
boolhasindex,
121121
TransactionIdfrozenxid);
122-
externvoidvacuum_set_xid_limits(VacuumStmt*vacstmt,boolsharedRel,
122+
externvoidvacuum_set_xid_limits(intfreeze_min_age,boolsharedRel,
123123
TransactionId*oldestXmin,
124124
TransactionId*freezeLimit);
125125
externvoidvac_update_datfrozenxid(void);

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