[Pgpool-general] Read-only explicit transactions

[Toshihiro Kitagawa]

On Wed, 20 Jul 2011 10:21:16 -0700
Josh Berkus <josh at agliodbs.com> wrote:

> Toshihiro,
> 
> > pgpool determines whether to load-balance or not in the first sentence of
> > multi-statement. So if "BEGIN" is the first sentence of multi-statement,
> > pgpool can not load-balance it.
> > 
> > For example, pgpool can load-balance the request if it's the following case:
> > 
> > BEGIN;
> > SELECT ...; SELECT ...; SELECT ...;
> > COMMIT;
> > 
> > pgpool-II 3.0 or later(Master/Slave mode) load-balances queries in
> > explicit transactions without special setting.
> > 
> > However, note that multi-statement must not include write-queries.
> > And, each "SELECT" query is sent to the same backend node,
> > because pgpool decides a load balancing node in every session.
> 
> Well, we're using 3.0.4, and the application controls read-only vs.
> read-write pretty well. So I feel confident that I can make the
> transactions operate correctly.
> 
> You're saying this will just work on 3.0.4?

Yes, of course.

-- 
Toshihiro Kitagawa
SRA OSS, Inc. Japan