Some usefull queries in performance monitoring

Some usefull queries in performance monitoring:
SELECT
d1.session_id,
d3.[text],
d1.login_time,
d1.login_name,
d2.wait_time,
d2.blocking_session_id,
d2.cpu_time,
d1.memory_usage,
d2.total_elapsed_time,
d2.reads,d2.writes,
d2.logical_reads,
d2.sql_handle
FROM sys.dm_exec_sessions d1
JOIN sys.dm_exec_requests d2 ON d1.session_id=d2.session_id
CROSS APPLY sys.dm_exec_sql_text(d2.sql_handle) d3

Idntify locking query:
select distinct
t1.session_id as THIS_IS_Blocked_session,
t1.status as Blocked_session_status,
t1.command as Blocked_session_command,
t1.DatabaseName,
t1.text as Blocked_session_text,
t2.session_id as BY_THIS_Blocking_session,
t2.status as Blocking_session_status,
t2.command as Blocking_session_command,t2.DatabaseName,t2.text as Blocking_session_text
from
(
select
er.session_id,
er.status,
er.command,
DB_NAME(database_id) AS 'DatabaseName',
SUBSTRING(st.text, (er.statement_start_offset/2)+1,((CASE er.statement_end_offset WHEN -1 THEN DATALENGTH(st.text) ELSE er.statement_end_offset END - er.statement_start_offset)/2) + 1) AS text
FROM
sys.dm_exec_requests AS er
CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) AS st
) as T1
join sysprocesses as s on t1.session_id = s.spid
join syslockinfo as l on s.spid = l.req_spid
join
(
select
er.session_id,
er.status,
er.command,
DB_NAME(database_id) AS 'DatabaseName',
SUBSTRING(st.text, (er.statement_start_offset/2)+1,((CASE er.statement_end_offset WHEN -1 THEN DATALENGTH(st.text) ELSE er.statement_end_offset END - er.statement_start_offset)/2) + 1) AS text
FROM
sys.dm_exec_requests AS er
CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) AS st
) as T2 on s.blocked = t2.session_id
where s.blocked >0