[Pgpool-general] Idea: peer-to-peer app architecture with pgpool?

[Jaume Sabater]

On Sat, Feb 14, 2009 at 12:35 AM, alex <koalillo at fastmail.fm> wrote:

> Oh, I was thinking in the possibility of active pgpools in all nodes.

That would result in replication problems and information mismatch.
pgpool-II is not, AFAIK, ready for active-active clusters, but for
active-pasive clusters. Of course, wait for Tatsuo's reply as he will
be the one to confirm my thoughts.

> This way, each app server talks to a pgpool instance on the same node,
> with no load balancing- load balancing is taken care of via app server
> load balancing.
>
> Ascii drawing:
>
>    /--> App --> PgPool ---> PG
>    |                    |
>    |                    | Write queries
>    |                    |
> LB +--> App --> PgPool --> PG
>    |                    |
>    |                    | Write queries
>    |                    |
>    \--> App --> PgPool --> PG
>
>
> Read queries incur no network latency, app is load balanced. Nodes are
> homogeneous.

You can prevent this from happening by setting load balance off but,
of course, you will only be using one node.

> Thoughts?

You are trying to get the best from an active-active cluster and an
active-passive cluster without any of the downsides, which is, AFAIK,
impossible :)

-- 
Jaume Sabater
http://linuxsilo.net/

"Ubi sapientas ibi libertas"