Re: PATCH: Make pg_stop_backup() archive wait optional

On Thu, Mar 23, 2017 at 12:37 AM, Stephen Frost <sfrost@snowman.net> wrote:
> David, all,
>
> * David Steele (david@pgmasters.net) wrote:
>> On 3/21/17 2:34 PM, Fujii Masao wrote:
>> >The patch basically looks good to me, but one comment is;
>> >backup.sgml (at least the description for "Making a non-exclusive
>> >low level backup) seems to need to be updated.
>>
>> Agreed.  Added in the attached patch and rebased on 8027556.

Thanks for updating the patch!

-SELECT * FROM pg_stop_backup(false);
+SELECT * FROM pg_stop_backup(false [, true ]);

I think that it's better to get rid of "[" and "]" from the above because
IMO this should be the command example that users actually can run.

+     If the backup process monitors the WAL archiving process independently,
+     the second parameter (which defaults to true) can be set to false to
+     prevent <function>pg_stop_backup</> from blocking until all WAL is
+     archived.  Instead, the function will return as soon as the stop backup
+     record is written to the WAL.  This option must be used with caution:
+     if WAL archiving is not monitored correctly then the result might be a
+     useless backup.

You added this descriptions into the step #4 in the non-exclusive
backup procedure.. But since the step #5 already explains how
pg_stop_backup has to do with WAL archiving, I think that it's better
to update (or add something like the above descriptions into)
the step #5. Thought?

+     If the backup process monitors the WAL archiving process independently,

Can we explain "monitor the WAL archiving process" part a bit more
explicitly? For example, "monitor and ensure that all WAL segment files
required for the backup are successfully archived".

> I've started looking at this.  Seems pretty straight-forward and will
> try to get it committed later today.

Thanks!

Regards,

-- 
Fujii Masao