1. SQL Server 2016 Query Data Store
11/28/2018
SQL Server 2016 Query Data Store
Sam Mesel –
Sr. SQL Premier Field Engineer
Microsoft
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Your Speaker Sam Mesel Senior Premier Field Engineer – SQL Server
Microsoft Services
LinkedIn:

3. Query Performance Issues have you ever …?
11/28/2018
Query Performance Issues have you ever …?
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

4. Have you ever need to Find queries that are using most resources ?
11/28/2018
Have you ever need to
Find queries that are using most resources ?
By CPU
By I/O (disk)
By Memory
By Duration
What tools are available to help investigation process ?
Traces
PSSDIAG / SQLNexus
DMVs
3rd Party monitoring tools
Anyone still using
Profiler Trace ?
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

5. Have you ever need to Find queries that are executed the most ?
11/28/2018
Have you ever need to
Find queries that are executed the most ?
Optimizations on queries that run 1,000s of times will lead to big gains
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

6. 11/28/2018
Have you ever need to
Find queries that have multiple execution plans ?
Use “Query Fingerprinting” and “Plan Fingerprinting”
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

7. Have you ever need to Find queries that regressed over time ?
11/28/2018
Have you ever need to
Find queries that regressed over time ?
This requires more elaborated solutions
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

8. DEMO: using basic DMVs to investigate Query Cache Contents 11/28/2018
Once this demo is complete, start OSTRESS workload to generate more queries
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

9. What if Query is no longer in cache ?
11/28/2018
Query is no longer in cache ?
Can the server be so busy that it flushes out queries from query cache ?
Would it be the case my server has too little memory ?
The SQL Server instance has restarted ?
The DBA has flushed the cache manually ?
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

10. Why does execution plan change ?
11/28/2018
Why does execution plan change ?
SQL Server Query Optimizer performs calculations to decide amongst several Execution plans, which one will be “good enough” for your query.
Once a plan is chosen, it will be placed in the query cache
As data changes, the query optimizer might select a different plan
As the schema changes, there will be different options for the query optimizer to consider
With new plan we can get better or worse performance
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11. Welcome to Query Data Store
11/28/2018
What can a DBA do ?
Welcome to Query Data Store
Create custom solution storing Query and Plan history
Baseline performance for each plan over time
Identify queries that became slower
Optimize those queries OR alternatively force a good known plan
Test solution:
Instance restarts
query recompiles
upgrades
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

12. 11/28/2018
Query Data Store
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

13. What is the Query Data Store?
11/28/2018
What is the Query Data Store?
A repository created on a database basis that collects
Queries and corresponding Execution plans
Runtime statistics
Ready to run visualizations on SSMS
Regressed Queries
Analysis by Resource Consumption
Tracked queries
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

14. What does Query Data Store do for DBA?
11/28/2018
What does Query Data Store do for DBA?
Quickly find query plan with performance regression
Easily fix plans by forcing previous plans
Provides statistics of Queries executed on last X hours
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

15. 11/28/2018
Using Query Data Store
Resource provides DBA with insight on queries and resource consumption
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

16. Query Data Store architecture
11/28/2018
Query Data Store architecture
Collects query texts and all relevant properties
Stores all plan choices and performance metrics
Works across restarts / upgrades / recompiles
Compile MSG
Execute MSG
Query Store
Durability latency controlled by DB option
DATA_FLUSH_INTERNAL_SECONDS
Async Write-Back
Compile
Execute
SQL
Plan Store
Runtime Stats
Query Store Schema
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

17. Query Data Store schema
Microsoft Ignite 2015
11/28/2018 3:55 PM
Query Data Store schema
internal tables
exposed views
Query Text
Query
Plan
Runtime
Stats
sys.
1 - n
1 - n
Compile stats:
query_store_query_text
query_context_settings
query_store_query
query_store_plan
Context
Settings
Runtime Stats Interval
Runtime stats:
query_store_runtime_stats_interval
query_store_runtime_stats
One Row Per Query Text Per Plan Affecting Option
(example: ANSI NULLS on/off)
One Row Per Plan (for each query)
One Row Per Plan Per Time Interval (example: 5 min)
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

18. Query Store Details
Plans and execution data are stored in the user database
Query store data persists reboots, upgrades, restores etc.
Plans and statistics are tracked at the database level
Query Store is configurable
Settings such as MAX_SIZE_MB, QUERY_CAPTURE_MODE, CLEANUP_POLICY allow you to decide how much data you want to store for how long
Can be configured either via the SSMS GUI or T-SQL scripts
Query Store can be viewed and managed via scripting or SSMS

19. What does Query Store Track?
Query Texts start at the first character of the first token of the statement; end at last character of last token
Comments before/after do not count
Spaces and comments inside *do* count
Context_settings contains one row per unique combination of plan-affecting settings
Different SET options cause multiple “queries” in the Query Store
Plan caching/recompilation behavior unaffected

20. What Gets Captured? Query Texts Query Plans
Runtime Statistics (per unit of time, default 1 hour)
Count of executions of each captured plan
For each metric: average, last, min, max, stddev
Metrics: duration, cpu_time, logical_io_reads, logical_io_writes, physical_io_reads, clr_time, DOP, query_max_used_memory, rowcount
Data is recorded when a query execution ends

21. DEMO: Query Data Store 11/28/2018
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

22. 11/28/2018
Scenarios
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

23. Key Usage Scenarios Find and fix query plan regressions
11/28/2018 3:55 PM
Key Usage Scenarios
Find and fix query plan regressions
Identify top resource consumers
Reduce risks with server upgrade
Deep analysis of workload patterns/perf
Short-term/tactical
Long-term/strategic
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

24. With Query Data Store 11/28/2018
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

25. Possibilities… Get full history of query execution
11/28/2018
Possibilities…
Get full history of query execution
Pinpoint expensive queries by resource
Check queries that have regressed
Easily force plans
© 2014 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

26. Questions