Re: Performance/Issues with CMP and JBoss - Mailing list pgsql-general

From Andy Dale
Subject Re: Performance/Issues with CMP and JBoss
Date
Msg-id faa313130608020409o35899f4fr86850846ffc4a9fb@mail.gmail.com
Whole thread Raw
In response to Re: Performance/Issues with CMP and JBoss  (Douglas McNaught <doug@mcnaught.org>)
Responses Re: Performance/Issues with CMP and JBoss  (Richard Huxton <dev@archonet.com>)
List pgsql-general
Hi,

I have performed some tests earlier on today, and i think the problem lies with Postgres and it's bad performance when being used with container managed persistence.  I am covinced of it being an issue with postgres because it works really well with MySQL and Hypersonic, but not with Postgres.  I have been reading around on the internet and it seems that Postgres does not work too well with container managed persistence, but surely all i have to do is just change some configuration settings, or can Postgres not be used with container managed persistence.

Thanks,

Andy

On 8/1/06, Douglas McNaught <doug@mcnaught.org> wrote:
"Andy Dale" <andy.dale@gmail.com> writes:

> The current problem we seem to have is that the data is persisted ok
> (or at least it seems to be in there with pgadmin), but cannot be
> read back out of the database all the time (in fact for about 90% of
> the time), the current behaviour of the application suggests it is
> trying to read it back out of the database (using
> EntityManager.find ()) before it has really been saved, and thus
> fails to find the data.  Do i have to tweak some settings in the
> postgres.conf file ? i have tried turning off fsync (i do not want
> to do this, for reliability reasons) and it performed far better.
> Can anyone advise me on the changes i need to make to speed up the
> inserting of data, i know that turning autocommit off is supposed to
> increase performance.

This is almost certainly a problem with your persistence layer rather
than with Postgres.  If you can see the data with PGAdmin then it's in
the database.  It may be that the transaction that saves the object is
not committing quickly, and so other connections don't see the object
until the commit happens.  But that's not the fault of Postgres.

-Doug

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