mysql [test10]>set ENABLE_EXCHANGE_PASS_THROUGH = true;
Query OK, 0 rows affected (0.00 sec)
mysql [test10]>SELECT count() FROM strings WHERE long IN (SELECT long FROM strings);
+----------+
| count(*) |
+----------+
| 10000000 |
+----------+
1 row in set (27.87 sec)
mysql [test10]>set ENABLE_EXCHANGE_PASS_THROUGH = false;
Query OK, 0 rows affected (0.00 sec)
mysql [test10]>SELECT count() FROM strings WHERE long IN (SELECT long FROM strings);
+----------+
| count(*) |
+----------+
| 10000000 |
+----------+
1 row in set (33.11 sec)
Proposed changes