| From: | David Rowley <dgrowleyml(at)gmail(dot)com> |
|---|---|
| To: | Thomas Munro <thomas(dot)munro(at)gmail(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, John Naylor <john(dot)naylor(at)enterprisedb(dot)com>, Peter Geoghegan <pg(at)bowt(dot)ie>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Robert Haas <rhaas(at)postgresql(dot)org> |
| Subject: | Re: A qsort template |
| Date: | 2022-04-11 00:25:33 |
| Message-ID: | CAApHDvpB98oDq_u=r_YrUhfF=3GZnvSpMFKWU9o-gDXhSc2vGA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, 11 Apr 2022 at 09:44, Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> David Rowley privately reported a performance regression when sorting
> single ints with a lot of duplicates, in a case that previously hit
> qsort_ssup() but now hits qsort_tuple_int32() and then has to call the
> tiebreaker comparator. Note that this comes up only for sorts in a
> query, not for eg index builds which always have to tiebreak on item
> ptr. I don't have data right now but that'd likely be due to:
I've now added this as an open item for v15.
David
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