Horton

Re: don't allocate HashAgg hash tables when running explain only

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Greg Stark <stark@mit.edu>
Cc: Alexey Bashtanov <bashtanov@imap.cc>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-11-19T06:47:51Z
Lists: pgsql-hackers 
On 19/11/2020 07:20, Greg Stark wrote:
> On Wed, 18 Nov 2020 at 05:40, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>>
>> On 13/11/2020 18:10, Alexey Bashtanov wrote:
>>>> I would appreciate if someone could have a look at the patch attached,
>>> which makes executor skip initializing hash tables when doing explain only.
>>
>> Makes sense. Committed, thanks for the patch!
> 
> Egads. That seems like a backpatchable bug fix to me. Have we been
> doing this all along?!

Yeah, I believe it's always been like that. Yeah, arguably it should be 
backpatched. I felt conservative and didn't backpatch, but feel free to 
do it if you think it should be.

- Heikki

Commits

  1. Skip allocating hash table in EXPLAIN-only mode.