https://bugs.openldap.org/show_bug.cgi?id=9237
--- Comment #4 from Howard Chu hyc@openldap.org --- (In reply to Ryan Tandy from comment #3)
Sounds like back-perl may not be as thread-unsafe as previously thought. Should probably investigate more before going ahead with this. Not sure how best to confirm whether safe or not...
That all depends on how libperl was built. Since that's highly site-dependent, I think it's fair to leave the backend disabled by default (removed from --enable-backends).