The following modification to add an additional index an attribute fails with the error messages pasted below: -------------------------- dn: olcDatabase={1}bdb,cn=config changetype: modify delete: olcdbindex olcDbIndex: cn pres,eq - add: olcdbindex olcDbIndex: cn pres,eq,sub -------------------------- modifying entry "olcDatabase={1}bdb,cn=config" ldap_modify: Other (e.g., implementation specific) error (80) additional info: <olcDbIndex> handler exited with 1 As far as I can see it fails because the old indexmask hat not yet been deleted from the bdb-struct. The ainfo_insert()-call in back-bdb/attr.c(bdb_attr_index_config()) returns with -1. Splitting the above modification in two separate operations works around that problem.