This document discusses hidden gems in SQL Server 2019, including lightweight query profiling, DBCC PAGE, dm_os_host_info, dm_os_schedulers, and QUERY OPTIMIZER COMPATIBILITY LEVEL. It provides demos of these lesser known features and notes that the string truncation error message is one of the most well-known hidden features. The author concludes that more hidden features will continue to be added to SQL Server.

1. Hidden Gems of SQL Server
2019
Odessa .Net User Group
Denis Reznik
Data Architect at Intapp, Inc.
Microsoft Data Platform MVP

2. About Me
• Denis Reznik
• Kyiv, Ukraine
• Data Architect at Intapp, Inc.
• Microsoft Data Platform MVP
• Co-Founder of Ukrainian Data Community Kyiv (PASS Chapter)
• PASS Regional Mentor, Central and Eastern Europe
• Co-author of “SQL Server MVP Deep Dives vol. 2”

3. SQL Server 2019
• Killer Features
• Big Data Clusters
• Secure Enclaves
• Intelligent QP
• Java Support
• String Truncation Error
Message (the most known
“hidden” feature)
• Hidden Features
• Lightweight Query Profiling
• DBCC PAGE
• dm_os_host_info
• dm_os_schedulers
• QUERY OPTIMIZER
COMPATIBILITY LEVEL

4. Lightweight Profiling

5. Session Level
Lightweight Profiling
• SQL Server 2014 – sys.dm_exec_query_profiles
• SQL Server 2016/2014 SP1 – Live Query Statistics
• Enable LQS in SSMS
• SET STATISTICS XML ON
• SET STATISTICS PROFILE ON
• query_post_execution_showplan event
• SQL Server 2016/2014 SP2 - query_thread_profile event
• SQL Server 2016 SP1 – query_thread_profile/TF 7412
• Lightweight query execution profiling
• https://blogs.msdn.microsoft.com/sql_server_team/query-progress-anytime-anywhere/
Server Level

6. DEMO
Lightweight Profiling

7. DEMO
DBCC PAGE

8. Global Allocation MAP (GAM)
GAM
Extent 1
Query 1
Query 2
LATCH
Wait
Extent 2
GAM 2 GAM 3
… …4GB 4GB

9. DEMO
dm_os_host_info

10. dm_os_schedulers

11. Query Execution
Thread Pool
Running
Suspended
Runnable
Scheduler
Logical CPU
Worker (Thread)
Connection

12. DEMO
dm_os_schedulers

13. QUERY OPTIMIZER COMPATIBILITY LEVEL

14. Statistics
500
1000
10
1200
800
1 800 2000 2800 4500 5400
SELECT * FROM Users
WHERE Id BETWEEN 2100 AND 2500
SELECT * FROM Users
WHERE Id BETWEEN 200 AND 5000

15. 500
1000
10
1200
800
1 800 2000 2800 4500 5400
Statistics
SELECT * FROM Users u
INNER JOIN Posts p
ON u.Id = p.OwnerUserId
WHERE u.DisplayName LIKE 'Jeff%'
10600
20000 10
1200 800
A G L S T ZZZZ
Users
Posts

16. DEMO
QUERY OPTIMIZER COMPATIBILITY LEVEL

17. SUMMARY
• Truncation Error Message (the most known “hidden” feature)
• Lightweight Query Profiling
• DBCC PAGE
• dm_os_host_info
• dm_os_schedulers
• QUERY OPTIMIZER COMPATIBILITY LEVEL
• More hidden features are coming..

18. Thank You!
Denis Reznik
Twitter: @denisreznik
Email: denisreznik@gmail.com
Blog: http://reznik.uneta.com.ua
Facebook: https://www.facebook.com/denis.reznik.5
LinkedIn: http://ua.linkedin.com/pub/denis-reznik/3/502/234