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

Commitd16a0c1

Browse files
committed
Verify that attribute counts match in ExecCopySlot
tts_virtual_copyslot() contained an Assert that checked that the srcslotcontained <= attributes than the dstslot. This seems to be backwards asif the srcslot contained fewer attributes then the dstslot could be leftwith stale Datum values from the previously stored tuple. It might makemore sense to allow the source to contain additional attributes and onlycopy the leading ones that also exist in the destination, however, that'snot what we're doing here.Here we just remove the Assert from tts_virtual_copyslot() and add anAssert to ExecCopySlot() to verify the attribute counts match. Theredoes not seem to be any places where the destination contains fewerattributes, so instead of going to the trouble of making the codeproperly handle this, let's just ensure the attribute counts match. Ifthis Assert fails then that will indicate that we do have cases thatrequire us to handle the srcslot with more attributes than the dstslot.It seems better to only write this code if there's a genuine requirementfor it rather than write it now only to leave it untested.Thanks to Andres Freund for helping with the analysis of this.Discussion:https://postgr.es/m/CAApHDvpMAvBL0T+TRORquyx1iqFQKMVTXtqNocOw0Pa2uh1heg@mail.gmail.com
1 parentd43bd09 commitd16a0c1

File tree

2 files changed

+9
-3
lines changed

2 files changed

+9
-3
lines changed

‎src/backend/executor/execTuples.c

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -253,8 +253,6 @@ tts_virtual_copyslot(TupleTableSlot *dstslot, TupleTableSlot *srcslot)
253253
{
254254
TupleDescsrcdesc=srcslot->tts_tupleDescriptor;
255255

256-
Assert(srcdesc->natts <=dstslot->tts_tupleDescriptor->natts);
257-
258256
tts_virtual_clear(dstslot);
259257

260258
slot_getallattrs(srcslot);

‎src/include/executor/tuptable.h

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -174,7 +174,8 @@ struct TupleTableSlotOps
174174

175175
/*
176176
* Copy the contents of the source slot into the destination slot's own
177-
* context. Invoked using callback of the destination slot.
177+
* context. Invoked using callback of the destination slot. 'dstslot' and
178+
* 'srcslot' can be assumed to have the same number of attributes.
178179
*/
179180
void(*copyslot) (TupleTableSlot*dstslot,TupleTableSlot*srcslot);
180181

@@ -477,12 +478,19 @@ ExecCopySlotMinimalTuple(TupleTableSlot *slot)
477478
*
478479
* If a source's system attributes are supposed to be accessed in the target
479480
* slot, the target slot and source slot types need to match.
481+
*
482+
* Currently, 'dstslot' and 'srcslot' must have the same number of attributes.
483+
* Future work could see this relaxed to allow the source to contain
484+
* additional attributes and have the code here only copy over the leading
485+
* attributes.
480486
*/
481487
staticinlineTupleTableSlot*
482488
ExecCopySlot(TupleTableSlot*dstslot,TupleTableSlot*srcslot)
483489
{
484490
Assert(!TTS_EMPTY(srcslot));
485491
Assert(srcslot!=dstslot);
492+
Assert(dstslot->tts_tupleDescriptor->natts==
493+
srcslot->tts_tupleDescriptor->natts);
486494

487495
dstslot->tts_ops->copyslot(dstslot,srcslot);
488496

0 commit comments

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