Horton

Re: CLUSTER sort on abbreviated expressions is broken

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-04-03T22:04:04Z
Lists: pgsql-hackers 
On Sun, Apr 3, 2022 at 8:22 PM John Naylor <john.naylor@enterprisedb.com> wrote:
> On Sun, Apr 3, 2022 at 11:05 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> > Independently of a problem with a recent commit, it seems that
> > $SUBJECT in all releases (well, I only tested as far back as 11).
>
> I can confirm the problem on v10 as well.

Thanks for confirming.  I got as far as seeing that the two calls to
FormIndexDatum() are producing garbage in {l,r}_index_values, in the
loop at the end of comparetup_cluster(), but I'll have to come back to
this after some other stuff.

Commits

  1. Fix CLUSTER tuplesorts on abbreviated expressions.

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