diff --git a/servers/slapd/back-bdb/dbcache.c b/servers/slapd/back-bdb/dbcache.c
index 10a937c101..a92cb44fbb 100644
--- a/servers/slapd/back-bdb/dbcache.c
+++ b/servers/slapd/back-bdb/dbcache.c
@@ -91,6 +91,7 @@ bdb_db_cache(
 #endif
 #ifdef BDB_IDL_MULTI
 	rc = db->bdi_db->set_flags( db->bdi_db, DB_DUP | DB_DUPSORT );
+	rc = db->bdi_db->set_dup_compare( db->bdi_db, bdb_bt_compare );
 #endif
 
 	file = ch_malloc( strlen( name ) + sizeof(BDB_SUFFIX) );