Re: Keep wal segments

Thanks Flavio!! I'll try these things up.

Prince Pathria
Systems Architect Evive +91 9478670472 goevive.com

On Fri, Sep 21, 2018 at 12:59 PM Flavio Henrique Araque Gurgel <
fhagur(at)gmail(dot)com> wrote:

> Em sex, 21 de set de 2018 às 09:19, Prince Pathria
> <prince(dot)pathria(at)goevive(dot)com> escreveu:
> >
> > Hi,
> >
> > On postgresql10, I'm facing issue of "requested WAL segment
> 000000010000007E0000003F has already been removed" a lot. I resync slaves
> with pg_basebackup and still some days after the same thing happens with
> same or other replica node.
> >
> > I have kept
> >
> > wal_keep_segment = 1024
> > wal_buffers = 16MB
> > min_wal_size = 1GB
> > max_wal_size = 2GB
> > archive_mode = on
> > archive_command = cp %p /var/lib/pgsql/10/archive/%f
> > wal_level = replica
> > synchronous_commit = on
> > synchronous_standby_names = 'pgslave01'
> >
> > Can I keep wal segments for some duration(eg 24 hours) ?
>
> Think about replication slots to deal with it:
>
> https://www.postgresql.org/docs/current/static/warm-standby.html#STREAMING-REPLICATION-SLOTS
>
> > I'm using two replicas with one in sync and other in potential state.Is
> one synchronous_standby_names fine?
>
> It seems ok, you'll have one synchronous replica.
>
> > Is there any option to remove archive wal after 30 days or 50GB?
>
> You have to keep wal that corresponds to your oldest basebackup.
> Consider using one of the backup solutions like Barman or pgbackrest.
> Barman works with basebackup and replication slots and you can set a
> retention policy for your backups, it handles wal keeping for you.
>
> > And how archiving the wal logs help? The missing segment is
> "000000010000007E0000003F" is in archive dir but how can I make it in use?
>
> You have to setup a restore_command to retrieve it from your archive:
>
> https://www.postgresql.org/docs/10/static/archive-recovery-settings.html#RESTORE-COMMAND
>