-----Original Message-----
From: Peter Geoghegan <pg@bowt.ie>
Sent: Thursday, July 22, 2021 12:14
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Jeff Davis <pgsql@j-davis.com>; ldh@laurent-hasson.com; David Rowley <dgrowleyml@gmail.com>; Justin Pryzby
<pryzby@telsasoft.com>;pgsql-performance@postgresql.org
Subject: Re: Big performance slowdown from 11.2 to 13.3
On Thu, Jul 22, 2021 at 8:45 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> That is ... weird. Maybe you have found a bug in the spill-to-disk
> logic; it's quite new after all. Can you extract a self-contained
> test case that behaves this way?
I wonder if this has something to do with the way that the input data is clustered. I recall noticing that that could
significantlyalter the behavior of HashAggs as of Postgres 13.
--
Peter Geoghegan
I could execute that test and re-cluster against the index. But I believe that's already done? Let me check.
Thank you,
Laurent.
