I've pushed the fix upstream. There are 2 commits:

The first adds logging that shows each time that the subselect fetch query fragment is created:
https://github.com/hibernate/hibernate-orm/commit/8fb8a158d3cebc979fdb6bfd127279cb84084802

The second commit is the fix:
https://github.com/hibernate/hibernate-orm/commit/0d5c35cdbc99d871515d9ed33d4d658fc2726253

In order to reproduce and verify the fix:
1) revert the second commit;
2) enabling trace logging for org.hibernate.engine.spi.SubselectFetch;
3) execute hibernate-core unit tests;
4) grep the hibernate-core test results for "SubselectFetch query" and note the number of occurrences;
5) apply the 2nd commit;
6) grep the hibernate-core test results for "SubselectFetch query" and note the number of occurrences; there should be about 1/4 as many occurrences.

Verified with EAP 6.4.8.CP.CR2

Carlo de Wolf <cdewolf> updated the status of jira JBEAP-3708 to Resolved

Jiri Pallich <jpallich> updated the status of jira JBEAP-3708 to Closed

Retroactively bulk-closing issues from released EAP 6.4 cumulative patches.