Slow running queries can drag down application performance and degrade user experience. As a DBA, it's important to monitor and optimize long running SQL statements.
In this post, I'll demonstrate how to find queries that have been executing for over 1 minute in SQL Server, using DMVs like sys.dm_exec_requests and sys.dm_exec_query_stats.
By querying these DMVs and joining to sys.dm_exec_sql_text, we can retrieve the full text of long running queries. Important details like total elapsed time, CPU time, reads and more are also returned.
The T-SQL code below filters for queries running longer than 1 minute and returns useful troubleshooting columns like the complete query plan. Reviewing this data helps identify the root cause like missing indexes, inefficient joins, repetitive scans etc.
/*https://www.dbascrolls.com*/
DECLARE @time_threshold INT = 60000; -- 1 minute in milliseconds
SELECT
r.session_id,
DB_NAME(r.database_id) AS dbname,
s.login_name,
r.blocking_session_id,
r.status,
s.program_name,
s.host_name,
r.transaction_isolation_level,
r.percent_complete,
r.start_time,
r.total_elapsed_time / 1000.0 AS total_elapsed_seconds,
r.wait_type,
r.last_wait_type,
r.command,
r.cpu_time,
r.reads,
r.writes,
r.logical_reads,
t.text AS query_text,
qp.query_plan
FROM
sys.dm_exec_requests r
JOIN
sys.dm_exec_sessions s ON r.session_id = s.session_id
CROSS APPLY
sys.dm_exec_sql_text(r.sql_handle) t
CROSS APPLY
sys.dm_exec_query_plan(r.plan_handle) qp
WHERE
r.total_elapsed_time > @time_threshold -- queries running longer than 1 minute
ORDER BY
r.total_elapsed_time DESC;
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