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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Mahendra Singh <mahi6run@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-01-07T15:59:22Z
Lists: pgsql-bugs, pgsql-hackers 
On Mon, Jan 6, 2020 at 7:22 PM Michael Paquier <michael@paquier.xyz> wrote:
> Okay for the first one, printing the OID sounds like a good idea.
> Like Tom, I would prefer keeping the relation name with "(null)" for
> the schema name.  Or even better, could we just print the OID all the
> time?  What's preventing us from showing that information in the first
> place?  And that still looks good to have when debugging issues IMO
> for orphaned entries.

I think we should have two different messages, rather than trying to
shoehorn things into one message using a fake schema name.

> For the second one, I would really wish that we keep the restriction
> put in place by a052f6c until we actually figure out how to make the
> operation safe in the ways we want it to work because this puts
> the catalogs into an inconsistent state for any object type able to
> use a temporary schema, like functions, domains etc. for example able
> to use "pg_temp" as a synonym for the temp namespace name.  And any
> connected user is able to do that.

So what?

> On top of that, except for tables,
> these could remain as orphaned entries after a crash, no?

Tables, too, although they want have storage any more. But your patch
in no way prevents that. It just makes it harder to fix when it does
happen. So I see no advantages of it.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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.