Whether SQL Blocking Session will be cleared by itself? - sql

Question

I can view the blocking session in our Production DB.
SELECT * FROM sys.sysprocesses WHERE spid = YOURSPID
I have not killed the session : Kill <SPID>
Does the blocking session will get clear by itself ?

Answer 1

It depends on the user(if any) who is active and who if any is executing the query. If there is any active user who has blocked the session then you have to kill the session for that user or else wait for him/his session to get finished. You can execute the sp_whoisactive to check the list of active users. And check if any user is blocking the session then you can explicitly kill the session for that user to get it working.
You can also refer: Identify the cause of SQL Server blocking.
This query is also a good way to analyze detailed information about
locks, and help you to identify the cause of a large number of blocks.
WITH [Blocking]
AS (SELECT w.[session_id]
,s.[original_login_name]
,s.[login_name]
,w.[wait_duration_ms]
,w.[wait_type]
,r.[status]
,r.[wait_resource]
,w.[resource_description]
,s.[program_name]
,w.[blocking_session_id]
,s.[host_name]
,r.[command]
,r.[percent_complete]
,r.[cpu_time]
,r.[total_elapsed_time]
,r.[reads]
,r.[writes]
,r.[logical_reads]
,r.[row_count]
,q.[text]
,q.[dbid]
,p.[query_plan]
,r.[plan_handle]
FROM [sys].[dm_os_waiting_tasks] w
INNER JOIN [sys].[dm_exec_sessions] s ON w.[session_id] = s.[session_id]
INNER JOIN [sys].[dm_exec_requests] r ON s.[session_id] = r.[session_id]
CROSS APPLY [sys].[dm_exec_sql_text](r.[plan_handle]) q
CROSS APPLY [sys].[dm_exec_query_plan](r.[plan_handle]) p
WHERE w.[session_id] > 50
AND w.[wait_type] NOT IN ('DBMIRROR_DBM_EVENT'
,'ASYNC_NETWORK_IO'))
SELECT b.[session_id] AS [WaitingSessionID]
,b.[blocking_session_id] AS [BlockingSessionID]
,b.[login_name] AS [WaitingUserSessionLogin]
,s1.[login_name] AS [BlockingUserSessionLogin]
,b.[original_login_name] AS [WaitingUserConnectionLogin]
,s1.[original_login_name] AS [BlockingSessionConnectionLogin]
,b.[wait_duration_ms] AS [WaitDuration]
,b.[wait_type] AS [WaitType]
,t.[request_mode] AS [WaitRequestMode]
,UPPER(b.[status]) AS [WaitingProcessStatus]
,UPPER(s1.[status]) AS [BlockingSessionStatus]
,b.[wait_resource] AS [WaitResource]
,t.[resource_type] AS [WaitResourceType]
,t.[resource_database_id] AS [WaitResourceDatabaseID]
,DB_NAME(t.[resource_database_id]) AS [WaitResourceDatabaseName]
,b.[resource_description] AS [WaitResourceDescription]
,b.[program_name] AS [WaitingSessionProgramName]
,s1.[program_name] AS [BlockingSessionProgramName]
,b.[host_name] AS [WaitingHost]
,s1.[host_name] AS [BlockingHost]
,b.[command] AS [WaitingCommandType]
,b.[text] AS [WaitingCommandText]
,b.[row_count] AS [WaitingCommandRowCount]
,b.[percent_complete] AS [WaitingCommandPercentComplete]
,b.[cpu_time] AS [WaitingCommandCPUTime]
,b.[total_elapsed_time] AS [WaitingCommandTotalElapsedTime]
,b.[reads] AS [WaitingCommandReads]
,b.[writes] AS [WaitingCommandWrites]
,b.[logical_reads] AS [WaitingCommandLogicalReads]
,b.[query_plan] AS [WaitingCommandQueryPlan]
,b.[plan_handle] AS [WaitingCommandPlanHandle]
FROM [Blocking] b
INNER JOIN [sys].[dm_exec_sessions] s1
ON b.[blocking_session_id] = s1.[session_id]
INNER JOIN [sys].[dm_tran_locks] t
ON t.[request_session_id] = b.[session_id]
WHERE t.[request_status] = 'WAIT'
GO