Two-to-three orders of magnitude speed improvement in the queryTableExists function for MySQL databases.
mysql> select count(*) from AddressUsage_0;
+----------+
| count(*) |
+----------+
| 38033514 |
+----------+
1 row in set (8.99 sec)
mysql> SELECT address_row IS NOT NULL AS tableexists FROM AddressUsage_0 LIMIT 1;
+-------------+
| tableexists |
+-------------+
| 1 |
+-------------+
1 row in set (0.01 sec)
mysql> SELECT table_name FROM information_schema.tables WHERE table_schema=DATABASE() AND table_name="AddressUsage_0";
+----------------+
| TABLE_NAME |
+----------------+
| AddressUsage_0 |
+----------------+
1 row in set (0.00 sec)The first option was used before. The third option is now implemented.