| From: | David Rowley <dgrowleyml(at)gmail(dot)com> |
|---|---|
| To: | sirisha chamarthi <sirichamarthi22(at)gmail(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com> |
| Subject: | Re: Prefetch the next tuple's memory during seqscans |
| Date: | 2022-11-23 07:44:04 |
| Message-ID: | CAApHDvrxLgFpm2-bC8ZfPRwVPOWQ=Eciu_4Uv3cBpSzDkg3V_g@mail.gmail.com |
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On Wed, 23 Nov 2022 at 20:29, sirisha chamarthi
<sirichamarthi22(at)gmail(dot)com> wrote:
> I ran your test1 exactly like your setup except the row count is 3000000 (with 13275 blocks). Shared_buffers is 128MB and the hardware configuration details at the bottom of the mail. It appears Master + 0001 + 0005 regressed compared to master slightly .
Thank you for running these tests.
Can you share if the plans used for these queries was a parallel plan?
I had set max_parallel_workers_per_gather to 0 to remove the
additional variability from parallel query.
Also, 13275 blocks is 104MBs, does EXPLAIN (ANALYZE, BUFFERS) indicate
that all pages were in shared buffers? I used pg_prewarm() to ensure
they were so that the runs were consistent.
David
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