Ldap crashes with "too many executing" errors

I am using Berkeleydb4.2 and openldap version 2.3.39 on a Centos 5 box with a bdb backend

The ldap server is used for backend authentication of users of imap server using sasl. Even though we have a similar setup working in many locations on a particular location I see ldap server hanging , apparently anytime and cannot be reproduced I kept ldap running in the debug mode I could see something like

-- connection_input: conn=5097 deferring operation: too many executing ber_get_next ber_get_next: tag 0x30 len 6 contents: connection_input: conn=5097 deferring operation: too many executing ber_get_next ---- When the ldap server hung.

I restart ldap and thing start working fine

How can I debug further

Thanks Ram