[pgpool-general: 549] Re: Hibernate and pgpool-II

Guillaume Lelarge guillaume at lelarge.info
Tue May 29 21:03:09 JST 2012


On Tue, 2012-05-29 at 07:49 +0900, Tatsuo Ishii wrote:
> > On 05/27/2012 10:31 AM, David Kerr wrote:
> >> On 5/27/2012 10:28 AM, Ludger Overbeck wrote:
> >>> Hi,
> >>>
> >>> I would like to know if anybody has ever used pgpool-II (in
> >>> Replication
> >>> Mode or Master/Slave Mode) with Hibernate? Does this cause any
> >>> problems?
> >>>
> >>> As far as I know in Hibernate SQL-statements (which are sent to the
> >>> database) are always issued in an explicit transaction. And as the FAQ
> >>> for pgpool says, that would mean that there is no load balancing in
> >>> replication mode. Is that correct?
> >>>
> >>> Instead I am thinking about using the Master/Slave mode with
> >>> synchronous
> >>> streaming replication to avoid that selects deliver stale data (as
> >>> with
> >>> asynchronous replication). Would this work?
> >>>
> >>> Thanks for your replies.
> >>
> >> I've started some testing with Hibernate + PgPool II in load balance /
> >> master server mode with async Streaming Replication and so far the
> >> results have been positive.
> >>
> >> Dave
> > 
> > 
> > Update on this:
> > 
> > Even though my test appeared to be load balancing, the log files show
> > that, in fact, it was not.
> > 
> > I suspect it's as you mentioned the explicit transactions in
> > hibernate. (I'm in Master/Slave mode.)
> 
> I don't know what was your test case but I'm sure pgpool-II 3.0 or
> later can do load balancing in streaming replication mode even in
> explicit transactions.

While I agree with you on this, it really depends on his workload. If he
does mostly write requests in master/slave mode, all the write queries
must be executed on the master, so most of the queries will happen on
the master, making it hard to appreciate the load balancing.


-- 
Guillaume
http://blog.guillaume.lelarge.info
http://www.dalibo.com



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