Re: Streaming base backups

Magnus Hagander <magnus(at)hagander(dot)net> writes:
>> Until we get integrated WAL streaming while the base backup is ongoing.
>> We don't know when that is (9.1 or future), but that's what we're aiming
>> to now, right?
>
> Yeah, it does sound like a plan. But to still allow both - streaming
> it in parallell will eat two connections, and I'm sure some people
> might consider that a higher cost.

Sure. Ah, tradeoffs :)

>> Well I still think that the easier setup we can offer here is to ship
>> with integrated libpq based archive and restore commands.  Those could
>> be bin/pg_walsender and bin/pg_walreceiver.  They would have some
>> switches to make them suitable for running in subprocesses of either the
>> base backup utility or the default libpq based archive daemon.
>
> Not sure why they'd run as an archive command and not like now as a
> replication client - but let's keep that out of this thread and in a
> new one :)

On the archive side you're right that it's not necessary, but it would
be to cater for the restore side. Sure enough, thinking about it some
more, what we would like here is for the standby to be able to talk to
the archive server (pg_streamsendrecv) rather than the primary, in order
to offload it. Ok scratch all that and get cascading support instead :)

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support