Re: WAL segments pile up during standalone mode

Bruce Momjian <bruce@momjian.us>

From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@commandprompt.com>, Robert Haas <robertmhaas@gmail.com>, Fujii Masao <masao.fujii@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2011-03-10T01:21:04Z
Lists: pgsql-hackers

Attachments

Tom Lane wrote:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
> > I admit I have no idea why these guys seem to run into wraparound
> > problems so much.
> 
> > On the other hand, I'm not sure that it would work to try to checkpoint
> > "during" vacuum, because the backend is in a transaction.  Maybe it
> > would work to force a checkpoint after each command, and between tables
> > in a multi-table vacuum (which is presumably a common thing to do in a
> > standalone backend) or something like that?
> 
> I really don't care for the idea of standalone mode doing *anything*
> the user didn't explicitly tell it to.  In its role as a disaster
> recovery tool, that's just a recipe for shooting yourself in the foot.
> 
> Perhaps this problem would be adequately addressed by documentation,
> ie suggest that when vacuuming very large tables in standalone mode,
> you should issue CHECKPOINT after each one.

I documented that there is no automatic background processing
(checkpoints) in single-user mode.  I did not mention the idea of
running checkpoints manually.  Applied patch attached.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +