Re: pgsql: Allow time delayed standbys and recovery

Thom Brown <thom@linux.com>

From: Thom Brown <thom@linux.com>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: pgsql-committers <pgsql-committers@postgresql.org>
Date: 2013-12-19T19:19:21Z
Lists: pgsql-hackers
On 12 December 2013 10:56, Simon Riggs <simon@2ndquadrant.com> wrote:
> Allow time delayed standbys and recovery
>
> Set min_recovery_apply_delay to force a delay in recovery apply for commit and
> restore point WAL records. Other records are replayed immediately. Delay is
> measured between WAL record time and local standby time.
>
> Robert Haas, Fabrízio de Royes Mello and Simon Riggs
> Detailed review by Mitsumasa Kondo

Could a note be added about the additional disk space requirements for
WAL on the standby?  If one is delaying replay, WAL files created over
the delayed period will build up in pg_xlog on the standby until
they're consumed upon replay, so considerations about storing those
additional files will need to be made.  It may otherwise trip up
anyone who, say, delays replay by 24 hours in a busy production
environment, and finds they have run out of disk space and no longer
have a valid standby.

-- 
Thom


Commits

  1. docs: Note the recovery_min_apply_delay bloats pg_wal.

  2. Allow time delayed standbys and recovery