Workflow migrations deadlock in the DB if there are active users on the system. System needs a "maintenance mode".

As we're migrating groups to Jira, I keep running into the same problem over and over again. Workflow migrations deadlock in the DB on user actions and I have to get our server bounced to unhang the system. Particularly in the early phases of a rollout as workflows are being migrated, this is a critical need.

There needs to be a way to put the system into a maintenance mode so that any existing end user sessions are terminated (along with the associated freeing of database locks) and new user logins need to be prevented. It would be handy if the system would put up a nice message along the lines of "I'm busy now...please come back later".

As a corollary to this, it would be handy to be able to get a list of logged on users and their last moment of activity although I freely acknowledge that this is a bit hard in a web environment.