pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Justin Pryzby <pryzby@telsasoft.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: David Rowley <dgrowleyml@gmail.com>
Cc: ldh@laurent-hasson.com <ldh@laurent-hasson.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Big performance slowdown from 11.2 to 13.3
Date: Thu, 22 Jul 2021 11:41:27 -0500
Message-ID: <20210722164127.GI19620@telsasoft.com> (raw)
In-Reply-To: <CAH2-WzmftijCna_aY-HyCUfswwfPCC4d2HjKab1cxM0QCFrRUQ@mail.gmail.com>
References: <MN2PR15MB2560778595BB7AF6E691B26785E39@MN2PR15MB2560.namprd15.prod.outlook.com>
	<MN2PR15MB2560D429866BD65A70574A6C85E49@MN2PR15MB2560.namprd15.prod.outlook.com>
	<CAApHDvqoF7y7SQjGT=940njnAd_CUcUG6oRYChcP_+eJyuNiug@mail.gmail.com>
	<MN2PR15MB25603D3CE06C8F9C312EA58985E49@MN2PR15MB2560.namprd15.prod.outlook.com>
	<MN2PR15MB2560E4574A6E2B5AED2C03CB85E49@MN2PR15MB2560.namprd15.prod.outlook.com>
	<784576.1626968702@sss.pgh.pa.us>
	<785218.1626969409@sss.pgh.pa.us>
	<CAApHDvo+Gb80BVPKYCwHbLa7a7ZXp9ziq9URrpQaKdvXsd46bg@mail.gmail.com>
	<786600.1626970898@sss.pgh.pa.us>
	<CAH2-WzmftijCna_aY-HyCUfswwfPCC4d2HjKab1cxM0QCFrRUQ@mail.gmail.com>

On Thu, Jul 22, 2021 at 09:36:02AM -0700, Peter Geoghegan wrote:
> I don't see how it's possible for get_hash_mem() to be unable to
> return a hash_mem value that could be represented by work_mem
> directly. MAX_KILOBYTES is an annoyingly low limit on Windows, where
> sizeof(long) is 4. But that's nothing new.

Oh.  So the problem seems to be that:

1) In v12, HashAgg now obeyes work_mem*hash_mem_multiplier;
2) Under windows, work_mem is limited to 2GB.

-- 
Justin





view thread (59+ messages)  latest in thread

Message-ID: <20210722164127.GI19620@telsasoft.com>
Permalink:  ../20210722164127.GI19620@telsasoft.com/
Also on:    postgresql.org/message-id/20210722164127.GI19620@telsasoft.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: pryzby@telsasoft.com, pg@bowt.ie, tgl@sss.pgh.pa.us, dgrowleyml@gmail.com, ldh@laurent-hasson.com
  Subject: Re: Big performance slowdown from 11.2 to 13.3
  In-Reply-To: <20210722164127.GI19620@telsasoft.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox