Lock wait timeout exceeded

[morganick]

Randomly I will get the following error from activerecord:

ActiveRecord::StatementInvalid: Mysql::Error: Lock wait timeout
exceeded; try restarting transaction

This is happening when the update is called on the users table to
update the perishable token and updated_at fields. However, the only
thing in the transaction is this update. I currently have indexes on
the primary key, username, persistance token, and last_request_at.
( Seemed like what was recommended looking through your examples.) As
far as I know I am optimized enough to only have single row locking
for that table.

Have any suggestions?

-- Nick