Re: [Postgres-xc-general] Composite table types, replicate + distribute.

[Michael P. <mic...@gm...>]

On Wed, Jul 4, 2012 at 11:05 PM, Joseph Glanville <
jos...@or...> wrote:

> On 4 July 2012 22:36, Andrei Martsinchyk <and...@gm...>
> wrote:
> > Hi Joseph,
> >
> > If you just need HA you may configure stanby's for your datanodes.
> > PostgresXC supports synchronous and asynchronous replication.
> > There is a pitfall, if you would try to make you database highly
> available
> > using combined hash/replicated distribution. Basically if replicated
> > datanode failed you would not able to write to the table. Coordinator
> would
> > not be able to update the replica.
> > With standby datanodes you may have your tables replicated and any change
> > will be automatically propagated to standby's, and system will work fine
> if
> > any standby fails. However you need an external solution to monitor
> master
> > datanodes and promote standby to failover.
>
> I understand this and is the reason why I was proposing a future
> movement towards a more integrated HA solution.
> It's more of a personal opinion rather than one purely ground in
> technical merit which is why I enquired as to whether this is
> compatible with XC goals.
>
> To me this has been a massive thing missing from the Open Source
> databases for a really long time and I would be happy to help make it
> happen.
>


> The biggest barrier has always been PostgreSQL's core team opposition
> to built in distributed operation, however is XC gains enough steam
> this might no longer be an issue.
>
What would be interesting here is to study the current integration of those
functionalities in 9.2 (I am going to merge the code with postgres 9.2 when
I'm more or less done with redistribution features) and then evaluate the
effort necessary to integrate our distribution functionalities more deeply
inside postgres code code. I believe it could be possible to integrate it
in such a way that your feature could be done at the same time.

That's only an idea though.
-- 
Michael Paquier
http://michael.otacoo.com