From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@bowt.ie>
cc: pgsql-committers <pgsql-committers@lists.postgresql.org>
Subject: Re: pgsql: Make heap TID a tiebreaker nbtree index column.
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Comments: In-reply-to Peter Geoghegan <pg@bowt.ie>
	message dated "Wed, 20 Mar 2019 11:00:06 -0700"
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Date: Wed, 20 Mar 2019 14:08:03 -0400
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Peter Geoghegan <pg@bowt.ie> writes:
> On Wed, Mar 20, 2019 at 10:05 AM Peter Geoghegan <pg@bowt.ie> wrote:
>> Make heap TID a tiebreaker nbtree index column.

> I see that this has caused SELinux test failures on rhinoceros (the
> ddl test fails). It looks like the output order is affected by the
> implementation details of nbtree, likely for some system catalog
> index. This is something that I've had to deal with in other places
> (with a lot of help from Tom).

The diffs all are related to the order of operations in a DROP OWNED BY
command, so I think blaming SELinux is just blaming the messenger.
This comes down to the point that we didn't do anything to ensure
drop order stability in shdepend-driven drops.  Maybe we need to be
honest about that.  Or do you have reason to think that your changes
will result in stability in that drop order anyway?  If so, why?

			regards, tom lane