Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY

On Thu, May 19, 2022 at 02:03:56PM +0200, Alvaro Herrera wrote:
> Hmm, yes, it's definitely possible that it is related.
>
> I'll have a look soon.

It took me some time to write a script to bisect that, but I have been
able to establish a correlation with d9d0762 that causes VACUUM to
ignore transactions doing some concurrent reindex operations.  I would
not be surprised to see that this is also related to some of the
reports we have seen lately with reindex operations.  There was one
with logical replication and missing records from a primary key, I
recall.

For the stable branches of 14 and 15, I would tend to play it safe and
revert d9d0762.  I have to admit that f9900df and c98763b stress me a
bit, and that we have not have anticipated all the ramifications of
this set of changes.  Thoughts?
--
Michael