Re: [GENERAL] Streaming Replication archive_command is really needed?

On Fri, Jul 21, 2017 at 8:15 AM, Andreas Kretschmer
<andreas@a-kretschmer.de> wrote:
> Am 21.07.2017 um 08:01 schrieb Michael Paquier:
>> "No" is not completely exact and lacks in details. There are two cases
>> where having an archive is helpful:
>> 1) The standby has disconnected from its primary for a time long
>> enough that WAL segments have been rotated by two completed
>> checkpoints. If that happens, when the standby reconnects it would
>> fail, and you would need to take a new base backup.
>
> you can prevent that using replication slots, but i'm pretty sure you
> (Michael) knows that ;-)
> http://paquier.xyz/postgresql-2/postgres-9-4-feature-highlight-replication-phydical-slots/

There is a typo on my URL here. Well that's too late to fix it even if
that's bad style.

>> 2) Backup strategies. Keeping a larger history set of WAL segments is
>> helpful for incremental backups, which is partially the point actually
>> raised upthread about PITR.
>
> Ack, that's right. Using both (streaming and wal-shipping/archiving) will
> make it more robust, and you have (with archiving) the posibility for PITR.
> BUT, you can build a streaming replication without archiving, even you can
> build a continuous backup using only streaming (Barman, streaming only
> mode).

Backup solutions developed by experts on the topic are paths to reliability.
--
Michael