Re: Implement targetlist SRFs using ROWS FROM() (was Changed SRF in targetlist handling)

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2016-08-29T15:48:56Z
Lists: pgsql-hackers
On 2016-08-29 12:56:25 +0300, Heikki Linnakangas wrote:
> On 08/28/2016 12:48 AM, Andres Freund wrote:
> > Attached is a significantly updated patch series (see the mail one up
> > for details about what this is, I don't want to quote it in its
> > entirety).
> > 
> > There's still some corner cases (DISTINCT + SRF, UNION/INTERSECT with
> > SRF) to test / implement and a good bit of code cleanup to do. But
> > feature wise it's pretty much complete.
> 
> Looks good

Thanks for the look!


> aside from the few FIXMEs, TODOs and XXXs

Those I pretty much know to handle.


> DIRTYs.

But I think this one is the "ordering" dependency information, and there
I don't yet have good idea.


> I think we need to come up with a better word for "unsrfify". That's quite a
> mouthful. Perhaps something as boring as "convert_srfs_to_function_rtes".

Yea, that was more of a working title. Maybe implement_targetlist_srfs()?


> Would it make sense for addRangeTableEntryForFunction() to take  a List of
> RangeFunctionElems as argument, now that we have such a struct? The
> lists-of-same-length approach gets a bit tedious.

Yea, I was thinking the same.


> Typos:
> s/fortfour/forfour
> s/Each element of this list a/ Each element of this list is a/

Thanks.

Greetings,

Andres Freund


Commits

  1. Remove obsoleted code relating to targetlist SRF evaluation.

  2. Doc: improve documentation of new SRF-in-tlist behavior.

  3. Move targetlist SRF handling from expression evaluation to new executor node.

  4. Don't split up SRFs when choosing to postpone SELECT output expressions.