Why semaphore table is not using MEMORY as storage engine? Drupal's table "semaphore" is using MyISAM (Drupal 6). I was wondering why it's not using MEMORY as storage engine?
The only thing that I could think of is that Drupal needs locking/semaphore data after MySQL restart. But the point with semaphore is that it should not have important data...

Am I missing something?
Drupal supports multiple database backends, but both MEMORY and the concept of storage engines as a whole is MySQL specific. Therefore, the Schema API has no support for specifying the storage engine.