There are several reasons for which indexing all root types in parallel turns out to be a bad idea.

• number of needed jdbc connections is unpredictable
• some other operations could run in parallel (index optimisation for eg)
• generates a very high amount of contention without a clear benefit

Discussed on http://lists.jboss.org/pipermail/hibernate-dev/2013-August/010229.html and related to HSEARCH-598