Re: [HACKERS] Infrastructure changes for recovery

Tom Lane <[email protected]> Thu, 18 Sep 2008 09:06:36 -0400
Newsgroups gmane.comp.db.postgresql.devel.patches,gmane.comp.db.postgresql.devel.general
Message-ID <[email protected]>
Simon Riggs <[email protected]> writes:
> Having some trouble trying to get a clean state change from recovery to
> normal mode.

> Startup needs to be able to write WAL at the end of recovery so it can
> write a ShutdownCheckpoint, yet must not be allowed to write WAL before
> that. Other services are still not fully up yet. So every other process
> apart from Startup musn't write WAL until Startup has fully completed
> its actions, which is sometime later.
> ...
> We *might* solve this by making the final checkpoint that Startup writes
> into an online checkpoint.

Do we really need a checkpoint there at all?  I can't recall right now
if there was a good reason why Vadim made it do that.  I have a feeling
that it might have had to do with an assumption that the recovery
environment was completely distinct from live environment; which is a
statement that's certainly not going to be true in a query-answering
slave.

			regards, tom lane

-- 
Sent via pgsql-patches mailing list ([email protected])
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-patches