Horton

Re: removal of dangling temp tables

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-12-15T03:42:03Z
Lists: pgsql-hackers 
On Fri, Dec 14, 2018 at 11:06:32PM -0300, Alvaro Herrera wrote:
> I did propose in my OP the idea of a PGPROC boolean flag that indicates
> whether the temp namespace has been set up.  If not, have autovac remove
> those tables.  I like this option better, but I fear it adds more
> ProcArrayLock contention.  Maybe I can just use a new LWLock to
> coordinate that particular member of the ProcGlobal array ... (but then
> it can no longer be a boolean.)

Isn't that what tempNamespaceId can be used for in PGPROC now?  The flag
would be set only when a backend creates a new temporary schema so as it
can be tracked as the owner of the schema.
--
Michael

Commits

  1. Have DISCARD ALL/TEMP remove leftover temp tables

  2. Make autovacuum more selective about temp tables to keep

  3. Make autovacuum more aggressive to remove orphaned temp tables

  4. autovacuum: Drop orphan temp tables more quickly but with more caution.