Horton

Re: BUG #16329: Valgrind detects an invalid read when building a gist index with buffering

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Pavel Borisov <pashkin.elfe@gmail.com>
Cc: Alexander Lakhin <exclusion@gmail.com>, pgsql-bugs@lists.postgresql.org, kyzevan23@mail.ru
Date: 2023-03-29T15:37:53Z
Lists: pgsql-bugs 
Pavel Borisov <pashkin.elfe@gmail.com> writes:
> So I think that the patch by Alexander will do the thing. I also added some
> comments to the code and removed extra context reset in gistBuildCallback
> (which is already done level down) to make things clear.

My apologies for having let this slip through the cracks.  I think
I'd wanted to understand why the committed version of the GiST
index tests doesn't expose the problem, and I never got time to
study that.  I still haven't tracked it down, but the proposed patch
seems clearly safe so I've gone ahead and pushed it.

I did use Alexander's original code change that just moved the
totals-incrementing.  It looks to me like gistProcessEmptyingQueue
is not guaranteed to reach the context reset, and I'd rather have
an extra reset than miss one.  (No-op context resets are cheap.)

			regards, tom lane

Commits

  1. Fix dereference of dangling pointer in GiST index buffering build.

  2. Fix GiST buffering build to work when there are included columns.

  3. Re-allow testing of GiST buffered builds.

  4. Add support for building GiST index by sorting.