Denis Reznik SQL Server 2017 Hidden Gems

Organizers Natalia Pogorelova Andriy Pogorelov Paul Stetsenko

Sponsors

About Me Denis Reznik Kyiv, Ukraine Data Architect at Intapp, Inc. But Originally from Kharkiv Region 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”

SQL Server 2017 Killer Features Hidden Features SQL Server on Linux Graph Database QP Improvements Hidden Features The most “Hidden” feature of SQL Server 2019 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

Hidden Features Importance STORY Hidden Features Importance

The most “Hidden” feature of SQL Server 2019 DEMO The most “Hidden” feature of SQL Server 2019

Lightweight Profiling

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/ SQL Server 2017 - ? SQL Server 2019 – Enabled by default Session Level Server Level

Lightweight Profiling DEMO Lightweight Profiling

DEMO File System Views

DEMO String Aggregate

DEMO TRIM

Version Store Space

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

DEMO Version Store Space

Transaction Log Statistics DEMO Transaction Log Statistics

CXPACKET and CXCONSUMER Waits

CXPACKET and CXCONSUMER Waits DEMO CXPACKET and CXCONSUMER Waits

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

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

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

Functions Troubleshooting DEMO Functions Troubleshooting

DEMO Row Goal

QUERY OPTIMIZER COMPATIBILITY LEVEL

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

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

QUERY OPTIMIZER COMPATIBILITY LEVEL DEMO QUERY OPTIMIZER COMPATIBILITY LEVEL

SUMMARY Hidden Features Importance Story 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

Sponsors

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