1. SQL Server Baselining, Benchmarking and Workload Analysis
Gianluca Sartori
sqlconsulting.it

2. Gianluca Sartori Independent SQL Server consultant
SQL Server MVP, MCTS, MCITP, MCT
Works with SQL Server since version 7
Scuderia Ferrari
Blog: spaghettidba.com
Twitter: @spaghettidba

3. AGENDA Baselining Workload Analysis Benchmarking
What happens in “normal” conditions?
Workload Analysis
How are applications and databases interacting with each other?
Benchmarking
What if…?

4. Health Check Why? When? How? Improve performance Improve manageability
Regularly  Assessment
Continuously  Monitoring
How?
A methodology is needed

5. Health Check

6. Baselining Let’s establish what’s normal 9/10/2018 6:34 PM
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

7. What is a baseline?
Describes system performance in «normal» conditions
Used a comparison basis
Monitoring
Troubleshooting
Trend Analysis and Capacity Planning

8. Creating a baseline What to capture? How to capture? How often?
Where to store the captured data?
How long to keep it?
How to analyze it?

9. What to capture? General information System SQL Server Version
HW (CPU, RAM, disk…)
SQL Server
Version and edition
Configuration options
Database inventory
File size and placement

10. What to capture? Performance indicators Wait Stats
Performance Counters
Dynamic Management Objects
Query Stats

11. Wait Stats DMV  sys.dm_os_wait_stats
Tracks time spent by processes in a wait queue
Wait times are cumulative (since last server restart)
Great starting point for troubleshooting
Allows to identify problems from their symptoms
Shows which areas need attention
Not all wait classes are meaningful!

12. Wait Stats Common wait classes Resource Class Example Locking LCK_*
LCK_M_S
LCK_M_X
Latching
LATCH_*
PAGELATCH_*
LATCH_EX
PAGELATCH_UP
I/O
PAGEIOLATCH_*
*_COMPLETION
WRITELOG
PAGEIOLATCH_SH
IO_COMPLETION
ASYNC_IO_COMPLETION
CPU
THREADPOOL
SOS_SCHEDULER_YIELD
Network
ASYNC_NETWORK_IO
Parallelism
CXPACKET

13. Demo
WAIT STATS

14. Performance Counters Which counters? CPU Memory Disk SQL – specific …
More than 400 in SQL Server 2016!!!

15. DMO sys.dm_os_ OS information sys.dm_io_ Disk performance
sys.dm_exec_ Sessions, requests, connections
sys.dm_db_ Database info
sys.dm_tran_ Transactions, locks
sys.dm_... Audits, broker, CDC, FileStream, FTS, HADR, Repl, RG, XE…
Not all DMOs are performance related

16. Which DMOs? 141 DMOs in SQL Server 2016!!! SELECT name ,type_desc
Periodic Table of SQL Server Dynamic Management Objects
141 DMOs in SQL Server 2016!!!
SELECT name
,type_desc
FROM sys.all_objects
WHERE name LIKE 'dm[_]%'
ORDER BY name

17. What to capture?
How do you work with 400 performance counters and 141 DMOs?
Glenn Berry’s Diagnostic Information Queries
Davide Mauri’s SYS2 DMVs
Brent Ozar’s sp_Blitz
Kendall van Dyke’s SQLPowerDoc

18. Performance Data Collector
Available in all editions (except Express)
Contains System Collection Sets
Extensible model, custom Collection Sets
Extended T-SQL Collector
Captures data at regular intervals
Data saved in a Management Datawarehouse
Multiple instances can share the same MDW
May be integrated with Utility Control Point
Comes with reports to read and analyze the data
Reports can be centralized on Reporting Services:

19. How long to keep the data?
It depends on
Available disk space
Depth of analysis required
Volatility of the environment

20. Which data participate the baseline?
Select a subset of the data captured for monitoring
Select baseline regularly
“Implicit” selection  previous day/week/month
“Explicit” selection  extract a snapshot
Only one baseline?
Depends on business cycle
Depends on applications

21. Business Cycle

22. Monitoring Baseline
Compare the instant value of the performance metric with its baseline
Baseline must be chosen keeping the business cycle in mind

23. Workload Analysis What drives the load on SQL Server?
9/10/2018 6:34 PM
Workload Analysis
What drives the load on SQL Server?
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

24. Workload Analysis Performance  effect Workload  cause
Workload analysis allows to correlate cause and effect
Outcome of analysis is a plan

25. Query Statistics DMV  sys.dm_exec_query_stats
Information on all queries in plan cache
Rank queries in terms of: IO
Reads
Writes
CPU
Execution count

26. Plan cache analysis Correlate wait stats and query stats
Identify problematic queries
Missing indexes
Implicit conversions
Identify application issues
“Plan cache bloat”
Since 2012, DTA can use plan cache as a source

27. Query Store New in SQL Server 2016
Data is persisted throughout restarts
Allows to find plan regressions
Allows “fixing” rogue plans with no effort

28. Demo
PLAN CACHE ANALYSIS

29. Trace Often query stats are not enough What to capture with traces?
Volatile
Don’t capture queries marked as RECOMPILE
What to capture with traces?
Events
Columns
Filters
Collection tools
Profiler vs. SQLTrace

30. Extended Events Introduced in SQL Server 2008 (eg: Audit)
Expose events deep inside SQLOS
Often not available otherwise
Lightweight
Configurable
Replacement for SQL Trace (since 2012)
Used to lack some features
Analysis tools
Replay tools
Now 100% covered

31. Workload Analysis What to analyze Analysis tools
Depends on what you captured
Correlate with performance counters
Analysis tools
RML Utilities (ReadTrace) Watch out for trace file version  conversion
PSSDIAG
SQL Nexus
ClearTrace

32. Demo
CLEARTRACE

33. Benchmarking Imagine new scenarios… 9/10/2018 6:34 PM
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

34. What is a benchmark? Describes performance in different scenarios
Evaluates whatif scenarios:
Hardware/Software Upgrade
Virtualization
Helps rating tuning efforts
Server-wide configuration changes
Addition/removal of indexes
Code changes

35. Performance benchmarking

36. Workload capture Which tool? Which events should you capture?
SQL Trace vs. Profiler  Prefer SQL Trace
Which events should you capture?
Which columns should you capture?
RML Utilities
Trace definition script
Backup the database
First issue a full backup, then start the trace
First run the trace, then issue a full backup
Filter the trace

37. Workload replay Prepare the test environment Must be a complete clone
Restore User Databases
Keep original database_id!
Logins
Watch out for orphaned users!
Jobs
SSIS Packages
Database Mail
Test environment must be
isolated from production!

38. Workload replay Which tool? Profiler RML Utilities - Ostress
Distributed Replay
Introduced in SQL Server 2012
Can replay a workload form multiple clients
Same query rate of the original trace (synchronization mode)

39. Distributed replay 3 core elements: Administration tool
Distributed Replay Controller
Distributed Replay Client

40. Workload replay
Which tool?

41. Baseline Capture Reset performance metrics
DBCC SQLPERF("sys.dm_os_wait_stats",CLEAR);
DBCC FREEPROCCACHE();
DBCC FREESYSTEMCACHE('ALL');
DBCC DROPCLEANBUFFERS();
Take a snapshot for each database
Start collection
Performance Monitor Collection Set
SQLTrace – RML Template

42. Benchmark Capture Revert to snapshot Apply changes
Start collection of performance metrics
Start replay

43. Benchmark Analysis Analysis = compare with Baseline Analysis tools:
RML Utilities
SQLNexus
ClearTrace
Qure Analyzer

44. Demo
QURE ANALYZER

45. Questions & Answers 9/10/2018 6:34 PM
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

46. Izpolnite anketo! Vam je bilo predavanje všeč?
Ste se naučili kaj novega?
Vaše mnenje nam veliko pomeni!
Da bo NT konferenca prihodnje leto še boljša, vas prosimo, da izpolnite anketo o zadovoljstvu, ki jo najdete v svojem NTK spletnem profilu.

47. 9/10/2018 6:34 PM
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.