Removing HSQLDB

[kukeltje]

In the ESB forum, this was started. What do 'we' think?

[camunda]

For me personally it doesn't matter to much, as long as there is some in memory db working out of the box... JavaDB maybe has teh advantage to be available automatically in Java?

On the other hand: People are now used to have HSQL, but when migrating to jBPM 4 switching would be OK I think...

[fady.matar]

Any in memory DB that supports transaction isolation would be fine. That's the main concern with hypersonic databases.

[estaub]

I'm with Bernd and Fady - jBPM4, in-memory, with isolation.

As soon as anyone gets seriously into multithreaded use of JBPM, they get hosed by HSQL. Its current status "in the box" makes it seem like it's the "reference database" for JBPM, which it definitely shouldn't be.

-Ed Staub

[tom.baeyens]

makes sense.

but i'm still in doubt about the availability and portability of JavaDB based solutions. Which libs do we ship with. Which versions of JVM's have which versions of JavaDB inside. In case of hsqldb we just ship the lib and we always know the exact version. So it's easier to test with.

On the other hand, we should be able to control this if we set up our continuous integration properly.

[fady.matar]

We could use H2 database http://www.h2database.com/ it's used within the SOA platform. Main features:
* Fast in memory
* Supports transactions isolation
* Clustering

And according to their performance charts, they perform much better than HSQL. What do you guys say?

[kukeltje]

JBoss should standardize on one DB. If SOA/ESB decided on H2, we should too.

[tom.baeyens]

we should work on all db's.

http://hudson.jboss.org/hudson/job/jbpm-pvm-jdk5/

there is currently also matrix set up for postgres. but it will be extended soon to a more full range soon. this db matrix project can't yet be published publicly because of a hudson limitation with matrix projects. as soon as that is fixed, the db matrix results will become publicly available as well just like the link above

[kukeltje]

Sorry, I did not mean we should ditch support on all other db's, just which one would be the 'default'...

[aguizar]

+1 to making H2 the default. It is not included in the JDK so we can ship it with whatever version we want.

As for JavaDB, I've yet to hear any good comment about it, large footprint and slow performance are cited instead. Its only advantage is probably the Apache license.

On the other hand, H2 will certainly require a larger footprint to support isolation, probably on par with JavaDB.

For unit tests, space is not as big a concern as time, so overall I prefer H2 over JavaDB.

I believe we should switch in the SOA branch first, for consistency with the ESB test environment and to better address the recent concurrency concerns. Once that is in a stable shape, we can merge the changes to head.

[tom.baeyens]

h2 seems like a good candidate.

Does anyone know if there is a company behind it ? From what i could find, it seems that only the creator Thomas Mueller is behind it. He had to stop working on hypersonic when he got hired to build pointbase. But what changed then since he's now able to build H(ypersonic) 2 ?

Another important feature that I would like is that in the in-memory mode, I can open up the database manager tool and inspect the in-memory database in a debug session in my ide. Does anyone know if that is supported with H2 ?

[fady.matar]

I have played around with it since yesterday and already created a seam application that uses it.

Another important feature that I would like is that in the in-memory mode, I can open up the database manager tool and inspect the in-memory database in a debug session in my ide. Does anyone know if that is supported with H2 ?

They have a pretty good web interface where you can manage your database on the fly, I already used it, and it's generic enough to support more than the H2 engine and is already bundled with the H2 distribution

[kukeltje]

Does anyone know if there is a company behind it ? From what i could find, it seems that only the creator Thomas Mueller is behind it.

Sounds familiar Tom? Maybe something for JBoss ;-)

[kukeltje]

Might I point to this thread again in the light of Thomas' last remark

[thomas.diesler]

Here a few OS databases in Java

http://java-source.net/open-source/database-engines