We have an identity generator using the new generator in hibernate 3.2.3. Our configuration looks like:

<generator class="org.hibernate.id.enhanced.SequenceStyleGenerator">
<param name="sequence_name">ev_sequence</param>
<param name="optimizer">pooled</param>
<param name="increment_size">20</param>
</generator>

We have a batch size set to a number larger than 1.

But our hibernate trace shows things like:

2007-04-27 13:24:44,949 DEBUG org.hibernate.jdbc.AbstractBatcher - Executing batch size: 1

The hibernate documentation says in Ch 13: "Note that Hibernate disables insert batching at the JDBC level transparently if you use an identiy identifier generator."

So what's the point of using pooling if we can't batch? Any help on this would be appreciated. We're about to do our own pooling hack to work around this if we can't find a fix.

We've just discovered that it isn't the identity generator that's causing our problem.

It's the fact that we have multiple inserts with a common identity (i.e. the tables are joined).

We still haven't figured out why batching isn't working though...

We're going through the hibernate code and in "AbstractEntityPersister" there is a statement:

"we can't batch joined inserts, *especially* not if it is an identity insert; nor can we batch statements where the expectation is based on an output param".

The question is - why not?

This is an existing hibernate issue.

See: http://opensource.atlassian.com/project ... owse/HHH-1