Re: oversight in parallel aggregate

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>
Cc: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: oversight in parallel aggregate
Date: 2016-04-05 20:09:11
Message-ID: CA+TgmoazOPr_dY2LEA+PTdm1WQgNPkd4sGxOtx7vUeYMvkySig@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Mon, Apr 4, 2016 at 9:09 PM, David Rowley
<david(dot)rowley(at)2ndquadrant(dot)com> wrote:
> On 5 April 2016 at 11:59, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> One of my EDB colleagues, while in the process of refactoring some
>> unrelated Advanced Server code, discovered that (1) there's no way to
>> mark an aggregate as anything other than parallel-unsafe but (2) it
>> doesn't matter because has_parallel_hazard ignores Aggrefs anyway.
>> These mistakes cancel each other out (sorta) if all of your aggregates
>> happen to be parallel-safe, but otherwise not so much. Barring
>> objections, I intend to speedily apply the attached patch to fix this.
>
> Thanks for working on this. I should have noticed this myself...
>
> I had a quick look at this and I manged to make this happen;
>
> david=# create aggregate mysum(int) (sfunc=int4pl, combinefunc=int4pl,
> stype=int, parallel);
> server closed the connection unexpectedly
>
> I've attached a fix, which makes the code a bit more simple, and also
> inline with the other code in DefineAggregate().

Thanks.

> I think there was also a couple of missing syntax synopsis in the docs
> too. I've added those.

The first one was indeed needed, but the second syntax doesn't
actually work, so I took that back out.

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

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Robbie Harwood 2016-04-05 20:12:51 Re: [PATCH v12] GSSAPI encryption support
Previous Message Fabrízio de Royes Mello 2016-04-05 19:55:31 Unused macros in src/include/access/transam.h