Horton

Re: A qsort template

John Naylor <john.naylor@enterprisedb.com>

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From: John Naylor <john.naylor@enterprisedb.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-07-02T02:32:31Z
Lists: pgsql-hackers 
On Thu, Jul 1, 2021 at 6:10 PM Thomas Munro <thomas.munro@gmail.com> wrote:

> One thing I'm wondering about is whether it's worth having stuff to
> support future experimentation like ST_SORT_SMALL_THRESHOLD and
> ST_COMPARE_RET_TYPE in the tree, or whether we should pare it back to
> the minimal changes that definitely produce results.  I think I'd like
> to keep those changes: even if it may be some time, possibly an
> infinite amount, before we figure out how to tune the thresholds
> profitably, giving them names instead of using magic numbers seems
> like progress.

I suspect if we experiment on two extremes of type "heaviness" (accessing
and comparing trivial or not), such as uint32 and tuplesort, we'll have a
pretty good idea what the parameters should be, if anything different. I'll
do some testing along those lines.

(BTW, I just realized I lied and sent a .patch file after all, oops)

--
John Naylor
EDB: http://www.enterprisedb.com

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.