Re: Documentation Update: Document pg_start_backup checkpoint behavior

Michael Renner wrote:
> Hi,
>
> small patch for the documentation describing the current pg_start_backup
> checkpoint behavior as per
> http://archives.postgresql.org//pgsql-general/2008-09/msg01124.php .
>
> Should we note down a TODO to revisit the current checkpoint handling?
>
> best regards,
> Michael

> diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
> index 02545f1..6ea9488 100644
> --- a/doc/src/sgml/backup.sgml
> +++ b/doc/src/sgml/backup.sgml
> @@ -737,12 +737,8 @@ SELECT pg_start_backup('label');
> (see the configuration parameter
> <xref linkend="guc-checkpoint-completion-target">). Usually
> this is what you want because it minimizes the impact on query
> - processing. If you just want to start the backup as soon as
> - possible, execute a <command>CHECKPOINT</> command
> - (which performs a checkpoint as quickly as possible) and then
> - immediately execute <function>pg_start_backup</>. Then there
> - will be very little for <function>pg_start_backup</>'s checkpoint
> - to do, and it won't take long.
> + processing. Unfortunately it's currently not possible to expedite
> + the checkpointing done by pg_start_backup.
> </para>
> </listitem>
> <listitem>

I have combined the above patch with another change that reports a
checkpoint is taking place:

test=> select pg_start_backup('12');
NOTICE: performing checkpoint
pg_start_backup
-----------------
0/2000020
(1 row)

Patch attached.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +