Re: Eager aggregation, take 3 - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Eager aggregation, take 3
Date
Msg-id CA+TgmoYdO68GtU9WZ1_a+gJs7fZ96sNraxyvVwu4iRYv4kYmLQ@mail.gmail.com
Whole thread Raw
In response to Re: Eager aggregation, take 3  (Richard Guo <guofenglinux@gmail.com>)
List pgsql-hackers
On Wed, Aug 28, 2024 at 10:26 PM Richard Guo <guofenglinux@gmail.com> wrote:
> Yeah, I'm concerned about this too.  In addition to the inaccuracies
> in aggregation estimates, our estimates for joins are sometimes not
> very accurate either.  All this are likely to result in regressions
> with eager aggregation in some cases.  Currently I don't have a good
> answer to this problem.  Maybe we can run some benchmarks first and
> investigate the regressions discovered on a case-by-case basis to better
> understand the specific issues.

While it's true that we can make mistakes during join estimation, I
believe aggregate estimation tends to be far worse.

--
Robert Haas
EDB: http://www.enterprisedb.com



pgsql-hackers by date:

Previous
From: David Rowley
Date:
Subject: Re: Make printtup a bit faster
Next
From: James Watt
Date:
Subject: [BUG] Security bugs affected version detected.