Horton

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

Oliver Ford <ojford@gmail.com>

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From: Oliver Ford <ojford@gmail.com>
To: Tatsuo Ishii <ishii@sraoss.co.jp>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>, vik@postgresfriends.org, andrew@tao11.riddles.org.uk, David Fetter <david@fetter.org>, Krasiyan Andreev <krasiyan@gmail.com>
Date: 2023-05-06T08:41:49Z
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 →

  1. Fix coding style with "else".

  2. Fix multi WinGetFuncArgInFrame/Partition calls with IGNORE NULLS.

  3. Fix Coverity issue reported in commit 2273fa32bce.

  4. Use ereport rather than elog in WinCheckAndInitializeNullTreatment.

  5. Avoid uninitialized-variable warnings from older compilers.

  6. Fix Coverity issues reported in commit 25a30bbd423.

  7. Improve EXPLAIN's display of window functions.

  8. Automatically generate node support functions

On Sat, 6 May 2023, 04:57 Tatsuo Ishii, <ishii@sraoss.co.jp> wrote:

> Attached is the patch to implement this (on top of your patch).
>
> test=# SELECT row_number() RESPECT NULLS OVER () FROM (SELECT 1) AS s;
> ERROR:  window function row_number cannot have RESPECT NULLS or IGNORE
> NULLS
>

The last time this was discussed (
https://www.postgresql.org/message-id/1037735.1610402426%40sss.pgh.pa.us)
it was suggested to make the feature generalizable, beyond what the
standard says it should be limited to.

With it generalizable, there would need to be extra checks for custom
functions, such as if they allow multiple column arguments (which I'll add
in v2 of the patch if the design's accepted).

So I think we need a consensus on whether to stick to limiting it to
several specific functions, or making it generalized yet agreeing the rules
to limit it (such as no agg functions, and no functions with multiple
column arguments).