In our application we are using @ManyToMany(fetch = FetchType.LAZY) on an association and we are also using @NotFound(action = NotFoundAction.IGNORE) since there are some non-existing referenced objects in the database. After upgrading to 5.6.6, the associated objects are eagerly loaded, causing the corresponding feature to be slowed down by 500 to 1000 times.

This behavior change seems to be caused by the fix of https://hibernate.atlassian.net/browse/HHH-15060 , in which lazy load is disabled when @NotFound is specified (source here).

Due to the limit of existing data we have to NotFoundAction.IGNORE so this is a blocking issue for us.