Re: prepared statements

Christian Dannemann wrote:
> Hello All,
>
> We are currently experimenting with a postgresql cluster database
> (pgcluster 1.5rc11).
>
> The cluster replicates all prepared statements across all database
> servers (which makes sense if they are for updates and inserts). It also
> does this for normal select statements.
>
> That means that when using prepared statements, there is absolutely NO
> gain from using a db cluster. Everything is executed in every database.
> And there is the additional overhead of replicating that across. So huge
> investment in hardware, and a performance loss is the gain from that :-(

In the future, I'd suggest doing more testing before making huge
investments in hardware...

> Our application is written in java and we use the jdbc postgresql driver.
>
> Now it appears that this driver issues ANY statement as a prepared
> statement. I've tried to switch this off but to no avail. This is a huge
> nightmare and I don't quite understand why it is deemed necessary to
> issue every simple select statement as a prepared statement.

As Kris said, you really should be blaming pgcluster, and you can set
the protocolVersion parameter if you need to.

There's better alternatives to pgcluster, for example Sequoia
(http://sequoia.continuent.org/), or Slony (http://slony.info/)

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com