Re: Sync Rep v17

On Sat, 2011-02-19 at 23:26 -0500, Robert Haas wrote:

> I believe the problem is that the definition of IsOnSyncRepQueue is
> bogus, so that the loop in SyncRepWaitOnQueue always takes the first
> branch.

Sorry, don't see that. Jaime/Yeb fix applied.

> It was a little confusing to me setting this up that setting only
> synchronous_replication did nothing; I had to also set
> synchronous_standby_names.  We might need a cross-check there.  

I'm inclined to make an empty "synchronous_standby_names" mean that any
standby can become the sync standby. That seems more useful behaviour
and avoids the need for a cross-check (what exactly would we check??).

> I
> believe the docs for synchronous_replication also need some updating;
> this part appears to be out of date:
> 
> +        between primary and standby. The commit wait will last until
> the
> +        first reply from any standby. Multiple standby servers allow
> +        increased availability and possibly increase performance as
> well.

Agreed

> The words "on the primary" in the next sentence may not be necessary
> any more either, as I believe this parameter now has no effect
> anywhere else. 

Agreed

Docs changed: git://github.com/simon2ndQuadrant/postgres.git

-- Simon Riggs           http://www.2ndQuadrant.com/books/PostgreSQL Development, 24x7 Support, Training and Services