As with every good DBA's toolbox, my blocking list query using sys.dm_exec_requests is evolving.

I've added the following features:

  • The query execution plan of the active request in the QueryPlan column to the right.
  • Variable at the top which changes the relationship of the join between sys.dm_exec_sessions and sys.dm_exec_requests.
    • When set to 0, this query now displays all sessions, even those without active requests. I recently found this helpful when researching sleeping sessions that were blocking active sessions.
    • When set to 1, this query displays as it used to - only session and active request data.
  • Percent_Complete column - great for finding the progress of backup and restores
  • A few other minor helpful columns

declare @showallspids bit = 1


create table #ExecRequests (

id int IDENTITY(1,1) PRIMARY KEY

, session_id smallint not null

, request_id int null

, request_start_time datetime null

, login_time datetime not null

, status nvarchar(60) null

, command nvarchar(32) null

, sql_handle varbinary(64) null

, statement_start_offset int null

, statement_end_offset int null

, plan_handle varbinary (64) null

, database_id smallint null

, user_id int null

, blocking_session_id smallint null

, wait_type nvarchar (120) null

, wait_time_s int null

, wait_resource nvarchar(120) null

, cpu_time_s int null

, tot_time_s int null

, reads bigint null

, writes bigint null

, logical_reads bigint null

, [host_name] nvarchar(256) null

, [program_name] nvarchar(256) null

, blocking_these varchar(1000) NULL

, percent_complete int null

)


insert into #ExecRequests (session_id,request_id, request_start_time, login_time, status,command,sql_handle,statement_start_offset,statement_end_offset,plan_handle,database_id,user_id,blocking_session_id,wait_type,wait_time_s,wait_resource,cpu_time_s,tot_time_s,reads,writes,logical_reads,[host_name], [program_name] )

select s.session_id,request_id, r.start_time, s.login_time, r.status,command,sql_handle,statement_start_offset,statement_end_offset,plan_handle,s.database_id,user_id,blocking_session_id,wait_type,r.wait_time/60.,r.wait_resource ,r.cpu_time/60.,r.total_elapsed_time/60.,r.reads,r.writes,r.logical_reads,s.[host_name], s.[program_name]

from sys.dm_exec_sessions s

left outer join sys.dm_exec_requests r on r.session_id = s.session_id

where 1=1

and r.session_id > 35 --retrieve only user spids

and r.session_id <> @@SPID --ignore myself

and (@showallspids = 1 or r.session_id is not null)


update #ExecRequests

set blocking_these = LEFT((select isnull(convert(varchar(5), er.session_id),'') + ', '

from #ExecRequests er

where er.blocking_session_id = isnull(#ExecRequests.session_id ,0)

and er.blocking_session_id <> 0

FOR XML PATH('')

),1000)

select * from

(

select

r.session_id , r.host_name , r.program_name

, r.status

, r.blocking_these

, blocked_by = r.blocking_session_id

, r.wait_type , r.wait_resource

, DBName = db_name(r.database_id)

, r.command

, login_time

, request_start_time

, r.tot_time_s, r.wait_time_s, r.cpu_time_s, r.reads, r.writes, r.logical_reads

--, [fulltext] = est.[text]

, offsettext = CASE WHEN r.statement_start_offset = 0 and r.statement_end_offset= 0 THEN NULL

ELSE SUBSTRING ( est.[text]

, r.statement_start_offset/2 + 1,

CASE WHEN r.statement_end_offset = -1 THEN LEN (CONVERT(nvarchar(max), est.[text]))

ELSE r.statement_end_offset/2 - r.statement_start_offset/2 + 1

END )

END

, r.statement_start_offset, r.statement_end_offset

, cacheobjtype = LEFT (p.cacheobjtype + ' (' + p.objtype + ')', 35)

, QueryPlan = qp.query_plan

from #ExecRequests r

LEFT OUTER JOIN sys.dm_exec_cached_plans p ON p.plan_handle = r.plan_handle

OUTER APPLY sys.dm_exec_query_plan (r.plan_handle) qp

OUTER APPLY sys.dm_exec_sql_text (r.sql_handle) est

) a

order by LEN(blocking_these) desc, blocking_these desc, blocked_by desc, session_id asc
go


drop table #ExecRequests
GO

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