--- main/myisam_mrr.result 2019-05-14 15:44:52.232663568 +0530 +++ main/myisam_mrr.reject 2019-05-14 15:51:37.123563538 +0530 @@ -617,8 +617,8 @@ show status like 'handler_mrr%'; Variable_name Value Handler_mrr_init 1 -Handler_mrr_key_refills 1 -Handler_mrr_rowid_refills 1 +Handler_mrr_key_refills 0 +Handler_mrr_rowid_refills 0 set join_buffer_size=10; explain select sum(t1.b) from t0,t1 where t0.a=t1.a; id select_type table type possible_keys key key_len ref rows Extra