diff --git a/servers/slapd/back-bdb/dn2id.c b/servers/slapd/back-bdb/dn2id.c
index c16b8faf71..b60d535118 100644
--- a/servers/slapd/back-bdb/dn2id.c
+++ b/servers/slapd/back-bdb/dn2id.c
@@ -804,7 +804,7 @@ struct dn2id_cookie {
 	ID dbuf;
 	ID *ids;
 	void *ptr;
-	ID tmp[BDB_IDL_DB_SIZE];
+	ID tmp[BDB_IDL_UM_SIZE];
 	ID *buf;
 	DBT key;
 	DBT data;