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Commit5aeec4b

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committed
Patch VACUUM problem with moving chain of update tuples when source
and destination of a tuple lie on the same page.(Previously fixed in REL7_0 branch, now apply to current.)
1 parentcd57d64 commit5aeec4b

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1 file changed

+56
-22
lines changed

1 file changed

+56
-22
lines changed

‎src/backend/commands/vacuum.c

Lines changed: 56 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.168 2000/10/16 17:08:05 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.169 2000/10/22 19:49:43 tgl Exp $
1212
*
1313
1414
*-------------------------------------------------------------------------
@@ -669,6 +669,7 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
669669
tuple.t_data->t_cmin))
670670
{
671671
tuple.t_data->t_infomask |=HEAP_XMIN_INVALID;
672+
pgchanged= true;
672673
tupgone= true;
673674
}
674675
else
@@ -683,6 +684,7 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
683684
tuple.t_data->t_cmin))
684685
{
685686
tuple.t_data->t_infomask |=HEAP_XMIN_INVALID;
687+
pgchanged= true;
686688
tupgone= true;
687689
}
688690
else
@@ -730,8 +732,10 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
730732
{
731733
if (tuple.t_data->t_infomask&HEAP_MARKED_FOR_UPDATE)
732734
{
733-
pgchanged= true;
734735
tuple.t_data->t_infomask |=HEAP_XMAX_INVALID;
736+
tuple.t_data->t_infomask &=
737+
~(HEAP_XMAX_COMMITTED |HEAP_MARKED_FOR_UPDATE);
738+
pgchanged= true;
735739
}
736740
else
737741
tupgone= true;
@@ -746,6 +750,8 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
746750
if (tuple.t_data->t_infomask&HEAP_MARKED_FOR_UPDATE)
747751
{
748752
tuple.t_data->t_infomask |=HEAP_XMAX_INVALID;
753+
tuple.t_data->t_infomask &=
754+
~(HEAP_XMAX_COMMITTED |HEAP_MARKED_FOR_UPDATE);
749755
pgchanged= true;
750756
}
751757
else
@@ -759,6 +765,8 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
759765
* from crashed process. - vadim 06/02/97
760766
*/
761767
tuple.t_data->t_infomask |=HEAP_XMAX_INVALID;
768+
tuple.t_data->t_infomask &=
769+
~(HEAP_XMAX_COMMITTED |HEAP_MARKED_FOR_UPDATE);
762770
pgchanged= true;
763771
}
764772
else
@@ -818,6 +826,14 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
818826
{
819827
ItemIdlpp;
820828

829+
/*
830+
* Here we are building a temporary copy of the page with
831+
* dead tuples removed. Below we will apply
832+
* PageRepairFragmentation to the copy, so that we can
833+
* determine how much space will be available after
834+
* removal of dead tuples. But note we are NOT changing
835+
* the real page yet...
836+
*/
821837
if (tempPage== (Page)NULL)
822838
{
823839
SizepageSize;
@@ -827,14 +843,12 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
827843
memmove(tempPage,page,pageSize);
828844
}
829845

846+
/* mark it unused on the temp page */
830847
lpp=&(((PageHeader)tempPage)->pd_linp[offnum-1]);
831-
832-
/* mark it unused */
833848
lpp->lp_flags &= ~LP_USED;
834849

835850
vacpage->offsets[vacpage->offsets_free++]=offnum;
836851
tups_vacuumed++;
837-
838852
}
839853
else
840854
{
@@ -1397,20 +1411,45 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
13971411
tuple.t_datamcxt=NULL;
13981412
tuple.t_data= (HeapTupleHeader)PageGetItem(Cpage,Citemid);
13991413
tuple_len=tuple.t_len=ItemIdGetLength(Citemid);
1400-
/* Get page to move in */
1414+
1415+
/*
1416+
* make a copy of the source tuple, and then mark the
1417+
* source tuple MOVED_OFF.
1418+
*/
1419+
heap_copytuple_with_tuple(&tuple,&newtup);
1420+
1421+
RelationInvalidateHeapTuple(onerel,&tuple);
1422+
1423+
TransactionIdStore(myXID, (TransactionId*)&(tuple.t_data->t_cmin));
1424+
tuple.t_data->t_infomask &=
1425+
~(HEAP_XMIN_COMMITTED |HEAP_XMIN_INVALID |HEAP_MOVED_IN);
1426+
tuple.t_data->t_infomask |=HEAP_MOVED_OFF;
1427+
1428+
/* Get page to move to */
14011429
cur_buffer=ReadBuffer(onerel,destvacpage->blkno);
14021430

14031431
/*
14041432
* We should LockBuffer(cur_buffer) but don't, at the
1405-
* moment. If you'll do LockBuffer then UNLOCK it
1406-
* before index_insert: unique btree-s call heap_fetch
1407-
* to get t_infomask of inserted heap tuple !!!
1433+
* moment. This should be safe enough, since we have
1434+
* exclusive lock on the whole relation.
1435+
* If you'll do LockBuffer then UNLOCK it before
1436+
* index_insert: unique btree-s call heap_fetch to get
1437+
* t_infomask of inserted heap tuple !!!
14081438
*/
14091439
ToPage=BufferGetPage(cur_buffer);
14101440

14111441
/*
14121442
* If this page was not used before - clean it.
14131443
*
1444+
* NOTE: a nasty bug used to lurk here. It is possible
1445+
* for the source and destination pages to be the same
1446+
* (since this tuple-chain member can be on a page lower
1447+
* than the one we're currently processing in the outer
1448+
* loop). If that's true, then after vacuum_page() the
1449+
* source tuple will have been moved, and tuple.t_data
1450+
* will be pointing at garbage. Therefore we must do
1451+
* everything that uses tuple.t_data BEFORE this step!!
1452+
*
14141453
* This path is different from the other callers of
14151454
* vacuum_page, because we have already incremented the
14161455
* vacpage's offsets_used field to account for the
@@ -1428,8 +1467,11 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
14281467
vacuum_page(ToPage,destvacpage);
14291468
destvacpage->offsets_used=sv_offsets_used;
14301469
}
1431-
heap_copytuple_with_tuple(&tuple,&newtup);
1432-
RelationInvalidateHeapTuple(onerel,&tuple);
1470+
1471+
/*
1472+
* Update the state of the copied tuple, and store it
1473+
* on the destination page.
1474+
*/
14331475
TransactionIdStore(myXID, (TransactionId*)&(newtup.t_data->t_cmin));
14341476
newtup.t_data->t_infomask &=
14351477
~(HEAP_XMIN_COMMITTED |HEAP_XMIN_INVALID |HEAP_MOVED_OFF);
@@ -1450,20 +1492,15 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
14501492
last_move_dest_block=destvacpage->blkno;
14511493

14521494
/*
1453-
* Set t_ctid pointing to itself for last tuple in
1454-
* chain and to next tuple in chain otherwise.
1495+
* Setnew tuple'st_ctid pointing to itself for last
1496+
*tuple inchain, and to next tuple in chain otherwise.
14551497
*/
14561498
if (!ItemPointerIsValid(&Ctid))
14571499
newtup.t_data->t_ctid=newtup.t_self;
14581500
else
14591501
newtup.t_data->t_ctid=Ctid;
14601502
Ctid=newtup.t_self;
14611503

1462-
TransactionIdStore(myXID, (TransactionId*)&(tuple.t_data->t_cmin));
1463-
tuple.t_data->t_infomask &=
1464-
~(HEAP_XMIN_COMMITTED |HEAP_XMIN_INVALID |HEAP_MOVED_IN);
1465-
tuple.t_data->t_infomask |=HEAP_MOVED_OFF;
1466-
14671504
num_moved++;
14681505

14691506
/*
@@ -1504,10 +1541,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
15041541
}
15051542
}
15061543
WriteBuffer(cur_buffer);
1507-
if (Cbuf==buf)
1508-
ReleaseBuffer(Cbuf);
1509-
else
1510-
WriteBuffer(Cbuf);
1544+
WriteBuffer(Cbuf);
15111545
}
15121546
cur_buffer=InvalidBuffer;
15131547
pfree(vtmove);

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