Re: [PATCH] ANALYZE: hash-accelerate MCV tracking for equality-only types

From: John Naylor <johncnaylorls(at)gmail(dot)com>
To: Chengpeng Yan <chengpeng_yan(at)outlook(dot)com>
Cc: Tatsuya Kawata <kawatatatsuya0913(at)gmail(dot)com>, Ilia Evdokimov <ilya(dot)evdokimov(at)tantorlabs(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [PATCH] ANALYZE: hash-accelerate MCV tracking for equality-only types
Date: 2026-02-03 05:39:48
Message-ID: CANWCAZbzqpMtByniN7Vzrki56X0MuGCvJqP=aqvqxEgJ4VWdCw@mail.gmail.com
Views: Whole Thread | Raw Message | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Tue, Feb 3, 2026 at 11:33 AM Chengpeng Yan <chengpeng_yan(at)outlook(dot)com> wrote:
> That said, if other community members would prefer the simpler one-step
> update for readability, I’m happy to switch.

To evaluate that, it would be easier if the patch were split into two
commits, one with the simple step approach, and one that changes to
the other approach.

Also, we have some places that switch from e.g. an array to a hash
table once a collection gets above a certain threshold. In this case,
however, having less than 100 stat target is unheard of, in my
experience. It's only a tiny amount of code, but it doesn't seem worth
special-casing. Others may have a different opinion, and I'm not sure
we don't already have this behavior elsewhere.

--
John Naylor
Amazon Web Services

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Soumya S Murali 2026-02-03 05:42:11 Re: 001_password.pl fails with --without-readline
Previous Message John Naylor 2026-02-03 05:24:39 Re: More speedups for tuple deformation