Re: Stale description for pg_basebackup

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: masao.fujii@oss.nttdata.com
Cc: pgsql-hackers@lists.postgresql.org
Date: 2021-04-22T02:19:40Z
Lists: pgsql-hackers
At Thu, 22 Apr 2021 10:56:10 +0900, Fujii Masao <masao.fujii@oss.nttdata.com> wrote in 
> 
> 
> On 2021/04/22 9:25, Kyotaro Horiguchi wrote:
> >> What about the following description?
> >>
> >> -------------------
> >> When you are using -X none, if write activity on the primary is low,
> >> pg_basebackup may need to wait a long time for all WAL files required
> >> for
> >> the backup to be archived. It may be useful to run pg_switch_wal
> >> on the primary in order to trigger an immediate WAL file switch and
> >> archiving.
> >> -------------------
> > Looks far better.
> 
> Patch attached. I appended the following description to assist
> users to understand why pg_basebackup may need wait a long time
> when write activity is low on the primary.
> 
> ------------------
> pg_basebackup cannot force the standby to switch to
> a new WAL file at the end of backup.
> ------------------

I'm not sure which is the convention here, but I saw that some
function names in the doc are followed by parentheses (ie
pg_switch_wal()).

(prepended?) It seems a bit redundant but also a bit clearer. How
about the following simplification?

- It may be useful to run pg_switch_wal on the primary in order to
- trigger an immediate WAL file switch and archiving.
+ It may be useful to run pg_switch_wal() on the primary in that case.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center



Commits

  1. doc: Fix obsolete description about pg_basebackup.

  2. Make pg_stop_backup's wait_for_archive flag work on standbys.