diff --git a/cachedb/cachedb.h b/cachedb/cachedb.h
index 67acf49af8..72d4778c27 100644
--- a/cachedb/cachedb.h
+++ b/cachedb/cachedb.h
@@ -96,6 +96,8 @@ typedef struct cachedb_funcs_t {
 	 * @con: The cacheDB connection to use.
 	 * @filter: NULL, one or more AND'ed filters for the query.
 	 * @res: Will contain zero or more results.
+	 *
+	 * Return: 0 on success, -1 otherwise. @res is always safe to free.
 	 */
 	int (*query) (cachedb_con *con, const cdb_filter_t *filter, cdb_res_t *res);
 
@@ -116,6 +118,8 @@ typedef struct cachedb_funcs_t {
 	 * backends may only support row-level TTLs and set a TTL equal to the
 	 * max TTL between all input and existing DB TTL (e.g. MongoDB), others
 	 * may actually fully support dictionary-level TTLs (e.g. Cassandra).
+	 *
+	 * Return: 0 on success, -1 otherwise.
 	 */
 	int (*update) (cachedb_con *con, const cdb_filter_t *row_filter,
 	               const cdb_dict_t *pairs);
diff --git a/modules/cachedb_mongodb/cachedb_mongodb_dbase.c b/modules/cachedb_mongodb/cachedb_mongodb_dbase.c
index 46e8c92054..7c1116f0f1 100644
--- a/modules/cachedb_mongodb/cachedb_mongodb_dbase.c
+++ b/modules/cachedb_mongodb/cachedb_mongodb_dbase.c
@@ -1825,6 +1825,8 @@ int mongo_con_query(cachedb_con *con, const cdb_filter_t *filter,
 
 	LM_DBG("find all in %s\n", MONGO_NAMESPACE(con));
 
+	cdb_res_init(res);
+
 #if MONGOC_CHECK_VERSION(1, 5, 0)
 	/* TODO: test this! */
 	if (mongo_cdb_filter_to_bson(filter, &bson_filter) != 0) {
@@ -1839,8 +1841,6 @@ int mongo_con_query(cachedb_con *con, const cdb_filter_t *filter,
 	stop_expire_timer(start, mongo_exec_threshold, "MongoDB query rows",
 	                  con->url.s, con->url.len, 0);
 
-	cdb_res_init(res);
-
 	while (mongoc_cursor_next(cursor, &doc)) {
 #else
 	bson_t child;
@@ -1862,8 +1862,6 @@ int mongo_con_query(cachedb_con *con, const cdb_filter_t *filter,
 	stop_expire_timer(start, mongo_exec_threshold, "MongoDB query rows",
 	                  con->url.s, con->url.len, 0);
 
-	cdb_res_init(res);
-
 	while (mongoc_cursor_more(cursor) && mongoc_cursor_next(cursor, &doc)) {
 #endif
 		row = mongo_mk_cdb_row(doc);
diff --git a/modules/usrloc/udomain.c b/modules/usrloc/udomain.c
index 38f1b4287f..234b9c7e58 100644
--- a/modules/usrloc/udomain.c
+++ b/modules/usrloc/udomain.c
@@ -1175,7 +1175,10 @@ urecord_t* cachedb_load_urecord(db_con_t* _c, const udomain_t* _d,
 		return NULL;
 	}
 
-	cdbf.query(cdbc, aor_filter, &res);
+	if (cdbf.query(cdbc, aor_filter, &res) != 0) {
+		LM_ERR("query failed for AoR %.*s\n", _aor->len, _aor->s);
+		goto out_null;
+	}
 
 	/* TODO: implement use table _d->name */