Re: [HACKERS] Docs for archive_cleanup_command are poor

On 12 October 2010 23:28, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Sat, Oct 9, 2010 at 10:04 AM, Brendan Jurd <direvus(at)gmail(dot)com> wrote:
>> I have just set up HS+SR for the first time, and for the most part,
>> the docs were excellent.  The one exception for me was the discussion
>> of archive_cleanup_command.  This is a pretty important part of
>> constructing a healthy standby server, and IMO the docs don't give it
>> the treatment it deserves.
...

> Agreed.
>
> And, ISTM that we should mention that we must not just specify
> pg_archivecleanup in archive_cleanup_command when there are multiple
> standby servers. This is because, in that case, we must calculate
> the oldest restart point in those standbys and delete the archived
> WAL files according to that point.

As promised, here is a patch to try to address $SUBJECT.

Summary of changes:

In 25.2.4. "Setting Up a Standby Server":

* Get rid of the extraneous short paragraph,
* move the full-size paragraph up to where the now-extinct short para was,
* add an archive_cleanup_command to the example recovery.conf,
* flesh out the wording,
* add links to 26.1 and F.22.

In 26.1. "Archive recovery settings":

* Add detail to the description of how it works,
* add an example recovery.conf snippet,
* per Fujii-san's comment, indicate that multi-standby setups require
more finesse,
* link to F.22.

In F.22. "pg_archivecleanup":

* Edit and clarify wording,
* standardise label for the <archivelocation> argument,
* again indicate the multi-standby issue,
* link to 25.2.

I'll drop this onto the next open commitfest. If it passes muster, it
sure wouldn't hurt to backpatch it to 9.0.

Cheers,
BJ