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

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mahendra Singh <mahi6run@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-12-26T17:51:56Z
Lists: pgsql-bugs, pgsql-hackers 
Mahendra Singh <mahi6run@gmail.com> writes:
> I think, we can add a regression test for this.
> postgres=# create temporary table temp(c1 int);
> CREATE TABLE
> postgres=# drop schema pg_temp_3 cascade ;
> ERROR:  cannot drop temporary namespace "pg_temp_3"
> postgres=#

No, we can't, because the particular temp namespace used by a given
session isn't stable.

> I thought that auto_vacuum wlll drop all
> the temp table schema but it is not drooping.

Generally speaking, once a particular pg_temp_N schema exists it's
never dropped, just recycled for use by subsequent sessions.

			regards, tom lane

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.