Re: Buffer usage detailed by RelKind in EXPLAIN ANALYZE BUFFERS

From: Andres Freund <andres(at)anarazel(dot)de>
To: Andrey Borodin <amborodin86(at)gmail(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Buffer usage detailed by RelKind in EXPLAIN ANALYZE BUFFERS
Date: 2023-02-14 00:39:46
Message-ID: 20230214003946.55zbbtnt3qfjkmpw@awork3.anarazel.de
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Hi,

On 2023-02-13 16:36:25 -0800, Andrey Borodin wrote:
> On Mon, Feb 13, 2023 at 4:29 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > > 1. Some more increments on hot paths. We have to add this tiny toll to
> > > every single buffer hit, but it will be seldom of any use.
> >
> > Additionally, I bet it slows down EXPLAIN (ANALYZE, BUFFERS) noticeably. It's
> > already quite expensive...
> >
>
> I think collection of instrumentation is done unconditionally.
> We always do that
> pgBufferUsage.shared_blks_hit++;
> when the buffer is in shared_buffers.

The problem I'm talking about is the increased overhead in InstrStopNode(),
due to BufferUsageAccumDiff() getting more expensive.

Andres

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Andres Freund 2023-02-14 00:43:10 Re: Adding "large" to PG_TEST_EXTRA
Previous Message Peter Smith 2023-02-14 00:38:06 Re: Adding "large" to PG_TEST_EXTRA