Hello, we had a long-running (several days) process doing add and modify operations in OpenLDAP 2.4.41 + LMDB backend + SLES 11.3.
I would note you're talking about OpenLDAP and LMDB releases that are over 4 years old, past which point numerous issues have been fixed for both.
LMDB 0.9.15 Release (2015/06/19) OpenLDAP 2.4.41 Release (2015/06/21) --Quanah -- Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: <http://www.symas.com>