Horton

Re: BUG #16104: Invalid DSA Memory Alloc Request in Parallel Hash

Tomas Vondra <tomas.vondra@2ndquadrant.com>

View thread View on postgr.es
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, Andres Freund <andres@anarazel.de>, James Coleman <jtc331@gmail.com>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2019-12-10T18:36:06Z
Lists: pgsql-bugs 
On Tue, Dec 10, 2019 at 02:35:16PM -0300, Alvaro Herrera wrote:
>On 2019-Dec-10, Tomas Vondra wrote:
>
>> It's probably still a good idea to do this, although I wonder if we
>> might start doing this only when actually running out of bits (and use
>> the current algorithm by default). But I have no idea if that would be
>> any cheaper, and it would add complexity.
>
>I'm under the impression that this patch is proposed for backpatching,
>and that in master we can simply increase the hash width.
>

Possibly, although AFAIK we don't have that patch yet, and I don't
recall any measurements (so it might have overhead too, not sure). But
it's true additional complexity might complicate backpatching.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Rotate instead of shifting hash join batch number.