ObjectWeb/Clustered JDBC

Peter Eisentraut wrote:

I was at the ObjectWeb Conference today; ObjectWeb
(http://www.objectweb.org) being a consortium that has amassed quite an
impressive array of open-source, Java-based middleware under their
umbrella, including for instance our old friend Enhydra. And they
regularly kept mentioning PostgreSQL in their presentations.

To those that are interested in distributed transactions/two-phase commit,
I recommend taking a look at Clustered JDBC
(http://c-jdbc.objectweb.org/). While this is not exactly the same thing,
it looks to be a pretty neat solution for a similar class of applications.
In particular, it provides redundancy, load balancing, caching, and even
database independence.

It is indeed a nice solution but it is far from ready yet.
Especially the disaster recovery mechanism and things such as adding new
masters need some more work.
What I really miss is "DECLARE CURSOR". Maybe it will be in there some
day :).
However, we have done some real testing with sync replication (4 x pg, 1
x oracle). It performed surprisingly well (the JDBC part, not the Oracle
one ;) ).
Maybe this will be something really useful within the next few months.

Cheers,

Hans

--
Cybertec Geschwinde u Schoenig
Ludo-Hartmannplatz 1/14, A-1160 Vienna, Austria
Tel: +43/2952/30706 or +43/660/816 40 77
www.cybertec.at, www.postgresql.at, kernel.cybertec.at

Hans,

I don't understand the statement about missing "DECLARE CURSOR" ? The
backend supports it?

Dave

Hans-Jï¿œrgen Schï¿œnig writes:

Especially the disaster recovery mechanism and things such as adding new
masters need some more work.

Yes, someone is working on automatic recovery (which would extend to
adding new masters by starting recovery from zero). In fact, they're just
across town from you (together.at).

--
Peter Eisentraut peter_e@gmx.net

Dave,

I know that the backend does - it is an essential feature.
Clustered JDBC parses the statement sent to it in order to find out what
to do with it. I have played around a little (mostly interactive shell).
You will find out that Clustered JDBC will complain in this case because
it doesn't know what to do with it. If you are a tool support load
balancing and this kind of stuff DECLARE CURSOR can be painful to
implement - especially across multiple transactions.
Is is a very weak point of the current beta version.

Regards,

Hans

Dave Cramer wrote:

Hans,

I don't understand the statement about missing "DECLARE CURSOR" ? The
backend supports it?

Dave
On Sun, 2003-11-23 at 12:12, Hans-J�rgen Sch�nig wrote:

Peter Eisentraut wrote:

I was at the ObjectWeb Conference today; ObjectWeb
(http://www.objectweb.org) being a consortium that has amassed quite an
impressive array of open-source, Java-based middleware under their
umbrella, including for instance our old friend Enhydra. And they
regularly kept mentioning PostgreSQL in their presentations.

To those that are interested in distributed transactions/two-phase commit,
I recommend taking a look at Clustered JDBC
(http://c-jdbc.objectweb.org/). While this is not exactly the same thing,
it looks to be a pretty neat solution for a similar class of applications.
In particular, it provides redundancy, load balancing, caching, and even
database independence.

It is indeed a nice solution but it is far from ready yet.
Especially the disaster recovery mechanism and things such as adding new
masters need some more work.
What I really miss is "DECLARE CURSOR". Maybe it will be in there some
day :).
However, we have done some real testing with sync replication (4 x pg, 1
x oracle). It performed surprisingly well (the JDBC part, not the Oracle
one ;) ).
Maybe this will be something really useful within the next few months.

Cheers,

Hans

--
Cybertec Geschwinde u Schoenig
Ludo-Hartmannplatz 1/14, A-1160 Vienna, Austria
Tel: +43/2952/30706 or +43/660/816 40 77
www.cybertec.at, www.postgresql.at, kernel.cybertec.at

Peter Eisentraut wrote:

Hans-Jï¿œrgen Schï¿œnig writes:

Especially the disaster recovery mechanism and things such as adding new
masters need some more work.

Yes, someone is working on automatic recovery (which would extend to
adding new masters by starting recovery from zero). In fact, they're just
across town from you (together.at).

Guess who has taught them PostgreSQL ;).

Hans

--
Cybertec Geschwinde u Schoenig
Ludo-Hartmannplatz 1/14, A-1160 Vienna, Austria
Tel: +43/2952/30706 or +43/660/816 40 77
www.cybertec.at, www.postgresql.at, kernel.cybertec.at