1. Denis Reznik
SQL Server 2017 Hidden Gems

3. 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”

4. SQL Server 2017 Killer Features Hidden Features SQL Server on Linux
Graph Database
QP Improvements
Hidden Features
The most “Hidden” feature of SQL Server 2017
Lightweight Profiling
File System Views
String Aggregation
String Trimming
Version Store Space
Log Statistics
Statistics Update/Create
CXCONSUMER and CXPACKET waits
Functions Troubleshooting
Row Goal
Compatibility Level

5. String Truncation Error Message
DEMO
String Truncation Error Message

6. Lightweight Profiling

7. 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
SQL Server ?
SQL Server 2019 – Enabled by default
Session Level
Server Level

8. Lightweight Profiling
DEMO
Lightweight Profiling

9. DEMO
File System Views

10. DEMO
String Aggregate

11. DEMO
TRIM

12. Version Store Space

13. Version Store Usage with SNAPSHOT
SELECT * FROM Users
WHERE City = 'Kyiv'
BEGIN TRAN
UPDATE Users
SET City = 'Krakow'
WHERE City = 'Kyiv' ID
City 1
Krakow 2 3 4 5 6
New York 7 ID
City 1
Kyiv 2
Krakow 3 4 5 6
New York 7 X
SELECT * FROM Users
WHERE City = 'Kyiv'
Version Store ID
City 1
Kyiv
tempdb

14. DEMO
Version Store Space

15. Transaction Log Statistics
DEMO
Transaction Log Statistics

16. CXPACKET and CXCONSUMER Waits

17. CXPACKET and CXCONSUMER Waits
DEMO
CXPACKET and CXCONSUMER Waits

18. Parallel Query Execution
Amdal’s Law 2s 1s
Thread 1
Thread 2
Thread 3
Thread 4

19. CX_PACKET (<2017) 2s 1s Thread 0 Thread 1 Thread 2 Thread 3
CXPACKET Wait
CXPACKET Wait
Thread 1
CXPACKET Wait
Thread 2
CXPACKET Wait
Thread 3
Thread 4
CXPACKET Wait

20. CX_PACKET 2017 2s 1s Thread 0 Thread 1 Thread 2 Thread 3 Thread 4
CXCONSUMER Wait
CXCONSUMER Wait
Thread 1
CXPACKET Wait
Thread 2
CXPACKET Wait
Thread 3
Thread 4
CXPACKET Wait

21. Functions Troubleshooting
DEMO
Functions Troubleshooting

22. DEMO
Row Goal

23. QUERY OPTIMIZER COMPATIBILITY LEVEL

24. Statistics SELECT * FROM Users WHERE Id BETWEEN 2100 AND 2500
800
2000
2800
4500
5400

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

26. QUERY OPTIMIZER COMPATIBILITY LEVEL
DEMO
QUERY OPTIMIZER COMPATIBILITY LEVEL

27. SUMMARY
Truncation Error Message (the most known “hidden” feature) Lightweight Profiling File System Views String Aggregation String Trimming Version Store Space Log Statistics Statistics Update/Create CXCONSUMER and CXPACKET waits Functions Troubleshooting Row Goal Compatibility Level

29. Thank You! Denis Reznik Twitter: @denisreznik
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