Empty a mysql table FAST

better_than_truncate

TRUNCATE is usually a fast operation (much faster than DELETE FROM). But sometimes it just hangs; 

TRUNCATE on tables with no FOREIGN KEYs should act fast: it translate to dropping the table and creating a new one (and it all depends on the MySQL version, see the manual).

Renaming a table (without Foreign Keys) is much faster if its large enough. Instead of:
```
TRUNCATE log_table
```
Do:
```
CREATE TABLE log_table_new LIKE log_table;
RENAME TABLE log_table TO log_table_old, log_table_new TO log_table;
DROP TABLE log_table_old;
```