Migration is an asychronous event: a request is issued for the task to migrate, and the task migrates only when it reaches a quiescent state. For the Cluster Edition, a quiescent state is one that:
Is not executing a query batch
Has no open transactions
Has no session-level temporary tables
Has no declared cursors
Has not changed its password since its initial connection
Has not run set user or set proxy
Is not bound to an engine using the logical process manager
Is not using ASE Active Messaging
Is not a logical connection associated with an inbound site handler
Has not kept a database open in single-user mode.