Execution of batch statements generates a misleading log info when the hibernate.jdbc.batch_size <= 'current batch size'.
There are two different behaviours:
if (hibernate.jdbc.batch_size == 'current batch size') the log generated tell us "No batched statements to execute" (BatchingBatch.doExecuteBacth())

if(hibernate.jdbc.batch_size < 'current batch size') the log generated tell us "Executing batch size: x" with 'x' being the difference between 'current batch size' and hibernate.jdbc.batch_size.

I think it's because in BatchingBatch.addToBacth() we have:
...
if ( batchPosition == batchSize )

...

And this execution is not being logged.
If the logging about "Executing batch size: x" is performed inside BatchingBatch.performExecution() method instead of BatchingBatch.doExecuteBatch(), the log generated is consistent.

Regards. Hernán.
I'll try to attach the test case soon.