Re: pg_rewind: confused about recovery.conf/restore_command

Rui DeSousa <rui(dot)desousa(at)icloud(dot)com> writes:

> Hi Jerry,
>
> That has been my experience as well; pg_rewind does not fetch the WAL
> files.

Hmmm, just prior to my email here last night was my 2nd attempt, taking
a few hours of r/d time to eventually conclude that I was
misunderstanding the docs :-)

A few mentions of recovery.conf in the docs themselves plus what I found
searching Google certainly left me with the impression that pg_rewind
itself knows how to try using a restore_command if found in a
recovery.conf file of the target system to fetch WALs.

> You can use following parameter to keep the most recent logs; i.e. a
> couple of hours worth. That will allow pg_rewind to work during that

Yup this is obvious and I tested same with OK results.

> time frame — If it is still missing a WAL file or two you can
> manually copy them over in a pinch.

Yes and in fact I used my restore_command to do so.

>
> wal_keep_segments
>
>
> p.s. I switched to using ZFS snapshots instead.

Oh, my site is quite familiar with FS or SAN/array snapshots and we use
them all the time.

Just felt like pg_rewind looked like something we should try.

I'll wait to see if others can shed more light on this.

Thanks

>
>

--
Jerry Sievers
Postgres DBA/Development Consulting
e: postgres(dot)consulting(at)comcast(dot)net
p: 312.241.7800