Re: WIP partial replication patch

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Boszormenyi Zoltan <zb@cybertec.at>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Hans-Juergen Schoenig <hs@cybertec.at>
Date: 2010-08-14T13:21:42Z
Lists: pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On Sat, Aug 14, 2010 at 08:40:24AM +0200, Boszormenyi Zoltan wrote:
>> And in this patch, the startup process only tries to connect
>> after signalling the postmaster that a consistent state is reached.
>> And the connection has a reasonable timeout built in.

> I don't think you currently can guarantee you allways have enough
> local WAL to even reach a consistent point.

Even if you do, the patch will malfunction (and perhaps corrupt the
database) while reading that WAL.  Yes, it'd work once you reach a
consistent database state, but bootstrapping a slave into that
condition will be far more painful than it is with the current
replication code.

			regards, tom lane