LDAP shutting down on CentOS

[Harkin Banks]

>From time-to-time, slapd is terminating.  I can't think of any reason for 
this and certainly no one is shutting it down on purpose.  I'm running 
CentOS 5.2.e15.  Below is a tail of openldap.log.  Any thoughts?  Thank you.

Jan 22 00:42:28 smtp.example.com <debug> slapd[11955]: <= 
bdb_inequality_candidates: (modifyTimestamp) not indexed
Jan 22 00:42:29 smtp.example.com <debug> slapd[11955]: <= 
bdb_inequality_candidates: (modifyTimestamp) not indexed
Jan 22 00:42:30 smtp.example.com <debug> slapd[11955]: <= 
bdb_inequality_candidates: (modifyTimestamp) not indexed
Jan 22 00:42:37 smtp.example.com <debug> slapd[11955]: daemon: shutdown 
requested and initiated.
Jan 22 00:42:37 smtp.example.com <debug> slapd[11955]: slapd shutdown: 
waiting for 0 threads to terminate
Jan 22 00:42:38 smtp.example.com <debug> slapd[11955]: slapd stopped.
Jan 22 00:42:39 smtp.example.com <debug> slapd[28288]: @(#) $OpenLDAP: slapd 
2.3.43 (Dec 18 2008 04:41:25) $
        kolab at vps.example.com:/kolab/RPM/TMP/openldap-2.3.43/servers/slapd