See who is blocking whom right now

When the phone rings and “SQL is hung”, start with the blocking chain — not with a reboot.

SELECT
    r.session_id,
    r.blocking_session_id,
    r.wait_type,
    r.wait_time,
    r.status,
    r.command,
    DB_NAME(r.database_id) AS database_name,
    t.text AS batch_text
FROM sys.dm_exec_requests AS r
CROSS APPLY sys.dm_exec_sql_text(r.sql_handle) AS t
WHERE r.blocking_session_id > 0
   OR r.session_id IN (
        SELECT blocking_session_id
        FROM sys.dm_exec_requests
        WHERE blocking_session_id > 0
   )
ORDER BY r.blocking_session_id, r.session_id;

Then:

1. Find the head blocker
2. Identify the transaction (open tran, long report, unexpected lock)
3. Decide: wait, kill (last resort), or fix the app pattern

For recurring blocking, fix isolation levels, indexing, and transaction scope — killing SPIDs is not a strategy.