Re: Strange issues with 9.2 pg_basebackup & replication

Fujii,

Wait, are you telling me that we *still* can't remaster from streaming replication? Why wasn't that fixed in 9.2?

And: if we still have to ship logs, what's the point in even having cascading replication?

----- Original Message -----
> On Wed, May 16, 2012 at 1:36 AM, Thom Brown <thom(at)linux(dot)com> wrote:
> > However, this isn't true when I restart the standby.  I've been
> > informed that this should work fine if a WAL archive has been
> > configured (which should be used anyway).
>
> The WAL archive should be shared by master-replica and
> replica-replica,
> and recovery_target_timeline should be set to latest in
> replica-replica.
> If you configure that way, replica-replica would successfully
> reconnect to
> master-replica with no need to restart it.
>
> > But one new problem I appear to have is that once I set up
> > archiving
> > and restart, then try pg_basebackup, it gets stuck and never shows
> > any
> > progress.  If I terminate pg_basebackup in this state and attempt
> > to
> > restart it more times than max_wal_senders, it can no longer run,
> > as
> > pg_basebackup didn't disconnect the stream, so ends up using all
> > senders.  And these show up in pg_stat_replication.  I have a
> > theory
> > that if archiving is enabled, restart postgres then generate some
> > WAL
> > to the point there is a file or two in the archive, pg_basebackup
> > can't stream anything.  Once I restart the server, it's fine and
> > continues as normal.  This has the same symptoms of the
> > "pg_basebackup
> > from running standby with streaming" issue.
>
> This seems to be caused by spread checkpoint which is requested by
> pg_basebackup. IOW, this looks a normal behavior rather than a bug
> or an issue. What if you specify "-c fast" option in pg_basebackup?
>
> Regards,
>
> --
> Fujii Masao
>