Horton

Re: A qsort template

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Daniel Gustafsson <daniel@yesql.se>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-03-11T18:58:47Z
Lists: pgsql-hackers 
Hi,

I wish we had the same for bsearch... :)


On 2021-03-03 17:17:13 +1300, Thomas Munro wrote:
> As for which cases are actually worth specialising, I've attached the
> example that Andres mentioned earlier; it seems like a reasonable
> candidate to go ahead and commit too, but I realised that I'd
> forgotten to attach it earlier.

> From 4cec5cb9a2e0c50726b7337fb8221281e155c4cd Mon Sep 17 00:00:00 2001
> From: Thomas Munro <thomas.munro@gmail.com>
> Date: Thu, 18 Feb 2021 14:47:28 +1300
> Subject: [PATCH] Specialize checkpointer sort functions.
> 
> When sorting a potentially large number of dirty buffers, the
> checkpointer can benefit from a faster sort routine.  One reported
> improvement on a large buffer pool system was 1.4s -> 0.6s.
> 
> Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com

Looks good to me.

Greetings,

Andres Freund

Commits

  1. Remove debug messages from tuplesort_sort_memtuples()

  2. Fix performance regression in tuplesort specializations

  3. Fix tuplesort optimization for CLUSTER-on-expression.

  4. Initial pgindent and pgperltidy run for v14.

  5. Specialize checkpointer sort functions.

  6. Use sort_template.h for qsort() and qsort_arg().

  7. Use sort_template.h for qsort_tuple() and qsort_ssup().

  8. Add sort_template.h for making sort functions.

  9. Use abbreviated keys for faster sorting of text datums.