Show blocking resources

USE [msdb]

SELECT  blocking.session_id AS blocking_session_id ,
    blocked.session_id AS blocked_session_id ,
    waitstats.wait_type AS blocking_resource ,
    waitstats.wait_duration_ms ,
    waitstats.resource_description ,
    blocked_cache.text AS blocked_text ,
    blocking_cache.text AS blocking_text
FROM    sys.dm_exec_connections AS blocking
    INNER JOIN sys.dm_exec_requests blocked
        ON blocking.session_id = blocked.blocking_session_id
    CROSS APPLY sys.dm_exec_sql_text(blocked.sql_handle)
                        blocked_cache
    CROSS APPLY sys.dm_exec_sql_text(blocking.most_recent_sql_handle)
                        blocking_cache
    INNER JOIN sys.dm_os_waiting_tasks waitstats
        ON waitstats.session_id = blocked.session_id