in the mysql-schema-4-sp.sql the procedure TigUserLogout is defined as:
create procedure TigUserLogout(_user_id varchar(2049) CHARSET utf8)
update tig_users set online_status = greatest(online_status - 1, 0), last_logout = CURRENT_TIMESTAMP where user_id = _user_id;
why in the where clause is used directly the "_user_id" (that is not indexed on mysql) instead of "sha1_user_id = sha1(lower(_user_id))" as done in the other stored procedures?
How are managed the SQL migrations from one release to another? There is any tracking to new SQL to execute when there is a new version of the server?