Your use of the Apex Debugger is subject to these
restrictions.
You can use the Apex
Debugger only with sandbox
orgs.
You can have only one active debugging session per org across all the org’s sandboxes. However, you can
purchase more sessions for your parent org. Each sandbox org can have only
one active session.
You can’t debug more than two threads at a time.
Your Apex Debugger session
times out if it’s left inactive. Under normal conditions, you’re allowed 1 hour of
inactivity. When your instance’s server is experiencing peak loads, the timeout limit can
be reduced to 30 minutes.
Your Apex Debugger session
times out after 4 hours, regardless of activity.
Salesforce can terminate debugging
sessions for maintenance purposes, with or without notice. You can’t initiate a new
debugging session until the maintenance is complete.
j