Re: Add RESPECT/IGNORE NULLS and FROM FIRST/LAST options

Tatsuo Ishii <ishii@postgresql.org>

From: Tatsuo Ishii <ishii@postgresql.org>

To: tgl@sss.pgh.pa.us

Cc: ojford@gmail.com, peter@eisentraut.org, li.evan.chao@gmail.com, krasiyan@gmail.com, vik@postgresfriends.org, andrew@tao11.riddles.org.uk, david@fetter.org, pgsql-hackers@lists.postgresql.org

Date: 2025-10-06T09:34:39Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Fix coding style with "else".
- 20628b62e46e 19 (unreleased) landed
Fix multi WinGetFuncArgInFrame/Partition calls with IGNORE NULLS.
- 2d7b247cb414 19 (unreleased) landed
Fix Coverity issue reported in commit 2273fa32bce.
- dd766a441d69 19 (unreleased) landed
Use ereport rather than elog in WinCheckAndInitializeNullTreatment.
- 5f3808646f67 19 (unreleased) landed
Avoid uninitialized-variable warnings from older compilers.
- 71540dcdcb22 19 (unreleased) cited
Fix Coverity issues reported in commit 25a30bbd423.
- 2273fa32bce7 19 (unreleased) landed
Improve EXPLAIN's display of window functions.
- 8b1b342544b6 18.0 cited
Automatically generate node support functions
- 964d01ae90c3 16.0 cited

> Thank you for the report!
> 
>> Coverity is not very happy with this patch.
>> It's complaining that the result of window_gettupleslot
>> is not checked, which seems valid:
>> 
>> 1503     			{
>> 1504     				if (fetch_tuple)
>>>>>     CID 1666587:         Error handling issues  (CHECKED_RETURN)
>>>>>     Calling "window_gettupleslot" without checking return value (as is done elsewhere 8 out of 9 times).
>> 1505     					window_gettupleslot(winobj, pos, slot);
>> 1506     				if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot))
>> 1507     					return -1;
> 
> Yes, I forgot to check the return value of window_gettupleslot.
> 
>> and also that WinGetFuncArgInPartition is dereferencing
>> a possibly-null "isout" pointer at several places, including
>> 
>>>>>     Dereferencing null pointer "isout".
>> 3806     				if (*isout)		/* out of partition? */
>> 
>>>>>     Dereferencing null pointer "isout".
>> 3817     	if (!*isout && set_mark)
>> 3818     		WinSetMarkPosition(winobj, abs_pos);
>> 
>>>>>     Dereferencing null pointer "isout".
>> 3817     	if (!*isout && set_mark)
>> 3818     		WinSetMarkPosition(winobj, abs_pos);
>> 
>> The latter complaints seem to be because some places in
>> WinGetFuncArgInPartition check for nullness of that pointer
>> and some do not.  That looks like at least a latent bug
>> to me.
> 
> Agreed.
> 
> Attached is a patch to fix the issue.

Please disregard the v1 patch. It includes a bug: If
WinGetFuncArgInPartition() is called with set_mark == true and isout
== NULL, WinSetMarkPosition() is not called by
WinGetFuncArgInPartition().

I will post v2 patch.

Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp