Re: WAL archive on slave

I can understand it will create duplicates, but it would also allow for
recovery from backups.

If a backup was taken at midnight, and promotion happened at 6am then
having archiving on the slave would allow log replay from the backup.

Log replay from the old master would potentially end up in the incorrect
timeline.

Although potentially merging the archive logs favoring the new master's
logs might fix this?

Either way, it seems the answer to my question is no.

Thanks for the help!

-James Sewell

On Monday, 10 February 2014, Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at> wrote:

> James Sewell wrote:
> > If it is the the only way that I could achieve what I wanted would be to
> set
> > wal_keep_segments high enough then they will all be archived on
> promotion?
>
> Even if you set wal_keep_segments high I don't think that the replayed
> WAL will be archived.
>
> > I'm still not sure why they wouldn't be archived on the slave, seen as
> they show up in the directory?
> > Is there a limitation I'm not thinking about here?
>
> I guess that the idea is that a cluster will only archive the WAL it
> generates. Typically, the primary would archive these (if you don't
> archive
> WAL on the primary, you're probably doing something wrong).
> So this would only lead to duplicates.
>
> Yours,
> Laurenz Albe
>

--

James Sewell,
PostgreSQL Team Lead / Solutions Architect
______________________________________

Level 2, 50 Queen St, Melbourne VIC 3000

*P *(+61) 3 8370 8000 *W* www.lisasoft.com *F *(+61) 3 8370 8099

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