Horton

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

Robert Haas <robertmhaas@gmail.com>

View thread View on postgr.es
From: Robert Haas <robertmhaas@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2017-01-19T00:05:52Z
Lists: pgsql-hackers 
On Wed, Jan 18, 2017 at 7:00 PM, Andres Freund <andres@anarazel.de> wrote:
>>So, one of the big reasons I use CASE is to avoid evaluating
>>expressions in cases where they might throw an ERROR.  Like, you know:
>>
>>CASE WHEN d != 0 THEN n / d ELSE NULL END
>>
>>I guess it's not the end of the world if that only works for
>>non-set-returning functions, but it's something to think about.
>
> That's already not reliable in a bunch of cases, particularly evaluation during planning...  Not saying that's good, but it is.

Whee!

:-)

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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.