Re: WAL segments pile up during standalone mode - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: WAL segments pile up during standalone mode
Date
Msg-id 201103100121.p2A1L4p26565@momjian.us
Whole thread Raw
In response to Re: WAL segments pile up during standalone mode  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
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. +
diff --git a/doc/src/sgml/ref/postgres-ref.sgml b/doc/src/sgml/ref/postgres-ref.sgml
index d332cba..bd4ae33 100644
*** a/doc/src/sgml/ref/postgres-ref.sgml
--- b/doc/src/sgml/ref/postgres-ref.sgml
*************** PostgreSQL documentation
*** 745,751 ****

     <para>
      Note that the single-user mode server does not provide sophisticated
!     line-editing features (no command history, for example).
     </para>
   </refsect1>

--- 745,754 ----

     <para>
      Note that the single-user mode server does not provide sophisticated
!     line-editing features (no command history, for example).
!     Single-User mode also does not do any background processing, like
!     automatic checkpoints.
!
     </para>
   </refsect1>


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