Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitcd96389

Browse files
committed
Fix confusion on different kinds of slots in IndexOnlyScans.
We used the same slot to store a tuple from the index, and to store atuple from the table. That's not OK. It worked with the heap, becauseheapam_getnextslot() stores a HeapTuple to the slot, and doesn't care howlarge the tts_values/nulls arrays are. But when I played with a toy tableAM implementation that used a virtual tuple, it caused memory overruns.In the passing, tidy up comments on the ioss_PscanLen fields.
1 parent6c0c283 commitcd96389

File tree

2 files changed

+17
-5
lines changed

2 files changed

+17
-5
lines changed

‎src/backend/executor/nodeIndexonlyscan.c‎

Lines changed: 13 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -166,10 +166,10 @@ IndexOnlyNext(IndexOnlyScanState *node)
166166
* Rats, we have to visit the heap to check visibility.
167167
*/
168168
InstrCountTuples2(node,1);
169-
if (!index_fetch_heap(scandesc,slot))
169+
if (!index_fetch_heap(scandesc,node->ioss_TableSlot))
170170
continue;/* no visible tuple, try next index entry */
171171

172-
ExecClearTuple(slot);
172+
ExecClearTuple(node->ioss_TableSlot);
173173

174174
/*
175175
* Only MVCC snapshots are supported here, so there should be no
@@ -528,7 +528,17 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
528528
*/
529529
tupDesc=ExecTypeFromTL(node->indextlist);
530530
ExecInitScanTupleSlot(estate,&indexstate->ss,tupDesc,
531-
table_slot_callbacks(currentRelation));
531+
&TTSOpsVirtual);
532+
533+
/*
534+
* We need another slot, in a format that's suitable for the table AM,
535+
* for when we need to fetch a tuple from the table for rechecking
536+
* visibility.
537+
*/
538+
indexstate->ioss_TableSlot=
539+
ExecAllocTableSlot(&estate->es_tupleTable,
540+
RelationGetDescr(currentRelation),
541+
table_slot_callbacks(currentRelation));
532542

533543
/*
534544
* Initialize result type and projection info. The node's targetlist will

‎src/include/nodes/execnodes.h‎

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1359,7 +1359,7 @@ typedef struct
13591359
*SortSupport for reordering ORDER BY exprs
13601360
*OrderByTypByVals is the datatype of order by expression pass-by-value?
13611361
*OrderByTypLens typlens of the datatypes of order by expressions
1362-
*pscan_len size of parallel index scan descriptor
1362+
*PscanLen size of parallel index scan descriptor
13631363
* ----------------
13641364
*/
13651365
typedefstructIndexScanState
@@ -1403,8 +1403,9 @@ typedef struct IndexScanState
14031403
*RuntimeContext expr context for evaling runtime Skeys
14041404
*RelationDesc index relation descriptor
14051405
*ScanDesc index scan descriptor
1406+
*TableSlot slot for holding tuples fetched from the table
14061407
*VMBuffer buffer in use for visibility map testing, if any
1407-
*ioss_PscanLenSize of parallel index-only scan descriptor
1408+
*PscanLensize of parallel index-only scan descriptor
14081409
* ----------------
14091410
*/
14101411
typedefstructIndexOnlyScanState
@@ -1421,6 +1422,7 @@ typedef struct IndexOnlyScanState
14211422
ExprContext*ioss_RuntimeContext;
14221423
Relationioss_RelationDesc;
14231424
structIndexScanDescData*ioss_ScanDesc;
1425+
TupleTableSlot*ioss_TableSlot;
14241426
Bufferioss_VMBuffer;
14251427
Sizeioss_PscanLen;
14261428
}IndexOnlyScanState;

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp