With these changes
SET @saved_cs_client= @@character_set_client;
will be classified as QUERY_TYPE_USERVAR_WRITE and
SELECT 1 AS c1 FROM t1 ORDER BY ( SELECT 1 AS c2 FROM
t1 GROUP BY GREATEST(LAST_INSERT_ID(), t1.a) ORDER BY
GREATEST(LAST_INSERT_ID(), t1.a) LIMIT 1);
will be classified as QUERY_TYPE_READ|QUERY_TYPE_MASTER_READ