- sys.dm_exec_requests (can be db specific session statuses)
- sys.dm_os_wait_stats (cumulative server wide wait types)
Running, Suspended, Runnable Circle
A thread is using the CPU (called RUNNING) until it needs to wait for a resource. It then moves to an unordered list of threads that are SUSPENDED. In the meantime, the next thread on the FIFO (first-in-first-out) queue of threads waiting for the CPU (called being RUNNABLE) is given the CPU and becomes RUNNING. If a thread on the SUSPENDED list is notified that it's resource is available, it becomes RUNNABLE and is put on the bottom of the RUNNABLE queue. Threads continue this clockwise movement from RUNNING to SUSPENDED to RUNNABLE to RUNNING again until the task is completed. You can see processes in these states using the sys.dm_exec_requests DMV.