sp_who reports on system processes. If a user’s command is being blocked by locks held by another task or worker process, the status column shows “lock sleep” to indicate that this task or worker process is waiting for an existing lock to be released.
The blk_spid or block_xloid column shows the process ID of the task or transaction holding the lock or locks.
You can add a user name parameter to get sp_who information about a particular Adaptive Server user. If you do not provide a user name, sp_who reports on all processes in Adaptive Server.
The sample output for sp_lock and sp_familylock in this chapter omits the class column to increase readability. The class column reports either the names of cursors that hold locks or “Non Cursor Lock.”