Horton

Re: Significant Execution Time Difference Between PG13.14 and PG16.4 for Query on information_schema Tables.

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Richard Guo <guofenglinux@gmail.com>, nikhil raj <nikhilraj474@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-08-27T23:57:53Z
Lists: pgsql-hackers, pgsql-general 
On Wed, 28 Aug 2024 at 11:37, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Oh, scratch that, I see you mean this is an additional way to do it
> not the only way to do it.  But I'm confused why it works for
>         t1.two+1 AS c1
> but not
>         t1.two+t2.two AS c1
> Those ought to look pretty much the same for this purpose.

The bms_overlap(pull_varnos(rcon->root, newnode), rcon->relids) test
is false with t1.two+1.  Looks like there needs to be a Var from t2
for the bms_overlap to be true

David

Commits

  1. Avoid inserting PlaceHolderVars in cases where pre-v16 PG did not.

  2. Remove one memoize test case added by commit 069d0ff02.