Horton

Re: Temporary tables prevent autovacuum, leading to XID wraparound

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-01-31T17:01:49Z
Lists: pgsql-hackers 
On Tue, Jan 30, 2018 at 7:04 PM, Tsunakawa, Takayuki
<tsunakawa.takay@jp.fujitsu.com> wrote:
> So a simple improvement would be to assign workers fairly to databases facing a wraparound risk, as Sawada-san suggested.

Is that always an improvement, or does it make some cases better and
others worse?

> One ultimate solution should be the undo-based MVCC that makes vacuuming unnecessary, which you proposed about a year ago...

And blogged about yesterday.

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

Commits

  1. Clarify comment about assignment and reset of temp namespace ID in MyProc

  2. Make autovacuum more aggressive to remove orphaned temp tables

  3. Don't count background workers against a user's connection limit.