Horton

Re: Assert failure due to "drop schema pg_temp_3 cascade" for temporary tables and \d+ is not showing any info after drooping temp table schema

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Mahendra Singh Thalor <mahi6run@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-02-28T23:21:38Z
Lists: pgsql-bugs, pgsql-hackers 
On Fri, Feb 28, 2020 at 01:45:29PM -0500, Tom Lane wrote:
> After poking around, I see there aren't any other callers.  But I think
> that the cause of this bug is clearly failure to think carefully about
> the different cases that isTempNamespaceInUse is recognizing, so that
> the right way to fix it is more like the attached.

Good idea, thanks.  Your suggestion looks good to me.

> In the back branches, we could leave isTempNamespaceInUse() in place
> but unused, just in case somebody is calling it.  I kind of doubt that
> anyone is, given the small usage in core, but maybe.

I doubt that there are any external callers, but I'd rather leave the
past API in place on back-branches.
--
Michael

Commits

  1. Avoid failure if autovacuum tries to access a just-dropped temp namespace.

  2. Revert "Forbid DROP SCHEMA on temporary namespaces"

  3. Forbid DROP SCHEMA on temporary namespaces

  4. Make autovacuum more aggressive to remove orphaned temp tables

  5. Code review for early drop of orphaned temp relations in autovacuum.