While trying to migrate to Hibernate 5.2.18 I observed a change in behavior for Joined table while using a batch size > 0.
Attached a simple test case with two entities, Resource, the parent, and FolderResource, the child.
The record in the child table is not inserted.
With Hibernate <= 5.2.14 the test case is ok (even with batch size > 0).
With Hibernate > 5.2.14 the test case fails if the batch size > 0, while it succeed with batch size = 0.
In the second case, the log shows this line:
INFO AbstractBatchImpl:201 - HHH000010: On release of batch it still contained JDBC statements
that is not present for Hibernate <= 5.2.14
As for HHH-13355, it is possible that this regression has been introduced in version 5.2.15, issues HHH-2558/HHH-5797 introduced changes in this regard.
Batch inserts should be disabled when using a sequence-identity ID generator.