1. SQLSaturday 393- May 16, 2015- Redmond, WA
Diagnosing Performance with Wait Statistics
SQLSaturday 393- May 16, Redmond, WA
Principal Database Architect at DB Best Technologies
Former Principal DBA at Outerwall, Inc
Former Sr. Product Consultant with Idera Software
Former Program Manager for SQL Server Certified Master program in Microsoft Learning
Former Sr. Production DBA / Operations Engineer at Microsoft (CSS)
Microsoft Certified Master: SQL Server 2008 / MCSM Charter: Data Platform
Co-founder of the SQL PASS Security Virtual Chapter
MCITP: Database Developer: SQL Server 2005 and 2008
MCITP: Database Administrator: SQL Server 2005 and 2008
MCSE: Data Platform
MVP 2014
Co-author of Pro SQL Server 2008 Mirroring
Former Idera ACE (Advisors & Community Educators)
2 time host of T-SQL Tuesday
Guest Professor at SQL University, summer 2010, spring/summer 2011
Speaker at SQL PASS Summit 2010, 2011, and 2012 including a pre-con in 2012
Speaker/Pre-con at SQLRally 2012
13+ years working with SQL Server
Writer for SQL Server Pro (formerly SQL Server Magazine)
Member: Mensa
Dog picture: Maggie and Woody
SQLCruise instructor: Seattle to Alaska 2012
Speaker at SQL Server Intelligence Conference in Seattle 2012
Blog:
Twitter:
Robert L Davis
Principal Database Architect
@SQLSoldier

2. Robert L Davis Principal Database Architect at DB Best Technologies Greater Seattle Area | Information Technology and Services
Past:
Blog:
Twitter:
LinkedIN:
Principal DBA at Outerwall, Inc.
P.M. SQL Server Master Certification Program at Microsoft
Sr. Database Administrator at Microsoft
@SQLSoldier
Principal Database Architect at DB Best Technologies
Former Principal DBA at Outerwall, Inc
Former Sr. Product Consultant with Idera Software
Former Program Manager for SQL Server Certified Master program in Microsoft Learning
Former Sr. Production DBA / Operations Engineer at Microsoft (CSS)
Microsoft Certified Master: SQL Server 2008 / MCSM Charter: Data Platform
Co-founder of the SQL PASS Security Virtual Chapter
MCITP: Database Developer: SQL Server 2005 and 2008
MCITP: Database Administrator: SQL Server 2005 and 2008
MCSE: Data Platform
MVP 2014
Co-author of Pro SQL Server 2008 Mirroring
Former Idera ACE (Advisors & Community Educators)
2 time host of T-SQL Tuesday
Guest Professor at SQL University, summer 2010, spring/summer 2011
Speaker at SQL PASS Summit 2010, 2011, and 2012 including a pre-con in 2012
Speaker/Pre-con at SQLRally 2012
13+ years working with SQL Server
Writer for SQL Server Pro (formerly SQL Server Magazine)
Member: Mensa
Dog picture: Maggie and Woody
SQLCruise instructor: Seattle to Alaska 2012
Speaker at SQL Server Intelligence Conference in Seattle 2012
Blog:
Twitter:

3. Diagnosing Performance with Wait Statistics
“Find the problem, FIX IT.
Identify another problem, FIX IT.
Repeat as necessary.”
~ Keenan Thompson
(Saturday Night Live)

4. Diagnosing Performance with Wait Statistics
Medical approach to troubleshooting

5. Diagnosing Performance with Wait Statistics
Medical approach to troubleshooting
Baseline vital statistics
Performance counters
DMV stats

6. Diagnosing Performance with Wait Statistics
Medical approach to troubleshooting
Baseline vital statistics
Performance counters
DMV stats
Recheck vital statistics and compare

7. Diagnosing Performance with Wait Statistics
Medical approach to troubleshooting
Baseline vital statistics
Performance counters
DMV stats
Recheck vital statistics and compare
Find deviations from the norm

8. Diagnosing Performance with Wait Statistics
Medical approach to troubleshooting
Baseline vital statistics
Performance counters
DMV stats
Recheck vital statistics and compare
Find deviations from the norm
Read more:

9. Diagnosing Performance with Wait Statistics
Baseline for Performance

10. Diagnosing Performance with Wait Statistics
Baseline for Performance
Processor(*)\% Processor Time
PhysicalDisk\Avg. Disk sec/Read
PhysicalDisk\Avg. Disk sec/Write
Memory\Pages/sec
Memory\Available Bytes
SQLServer:Buffer Manager\Page life expectancy
SQLServer:GeneralStatistics\Processes Blocked
SQLServer:Access Methods\Full Scans/sec
SQLServer:SQL Statistics\Batch requests/sec
SQLServer:Buffer Manager\Lazy writes/sec
SQLServer:Buffer Manager\Buffer Cache Hit Ratio
SQLServer:Databases (*)\Transactions/sec

11. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries

12. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
Wait statistics

13. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
Wait statistics
sys.dm_os_wait_stats
sys.dm_os_waiting_tasks
sys.dm_exec_requests
sys.dm_exec_sessions
sys.dm_exec_query_plan()
sys.dm_exec_sql_text()

14. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_wait_stats

15. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_wait_stats
Cumulative since last restart or reset

16. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_wait_stats
Cumulative since last restart or reset
DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR);

17. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_wait_stats
Cumulative since last restart or reset
DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR);
Total waits on server

18. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_wait_stats
Cumulative since last restart or reset
DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR);
Total waits on server
Take a delta to see how they are changing

19. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_wait_stats
Cumulative since last restart or reset
DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR);
Total waits on server
Take a delta to see how they are changing
signal_wait_time_ms
Time from when the waiting task has its resource until it starts running
Waiting on CPU thread

20. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_waiting_tasks

21. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_waiting_tasks
Tasks currently waiting on a resource

22. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_waiting_tasks
Tasks currently waiting on a resource
wait_duration_ms

23. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_waiting_tasks
Tasks currently waiting on a resource
wait_duration_ms
wait_type

24. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_waiting_tasks
Tasks currently waiting on a resource
wait_duration_ms
wait_type
blocking_session_id

25. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_os_waiting_tasks
Tasks currently waiting on a resource
wait_duration_ms
wait_type
blocking_session_id
resource_description

26. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_exec_requests

27. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_exec_requests
Currently active requests
Shows wait stats too!
session_id
request_id – for parallel tasks
start_time
status – suspended = waiting
command
database_id
blocking_session_id
wait_type
wait_time
last_wait_type – if not currently waiting
wait_resource

28. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_exec_sessions

29. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_exec_sessions
Currently active sessions
Shows client connection info
Not all sessions have a request
Has some performance stats cumulative over all requests for the entire session
program_name
is_user_process

30. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_exec_query_plan()
Query plan from cache
Requires plan_handle

31. Diagnosing Performance with Wait Statistics
Troubleshooting Slow Queries
sys.dm_exec_query_plan()
Query plan from cache
Requires plan_handle
sys.dm_exec_sql_text()
SQL text from cache
Requires sql_handle or plan_handle
Provides offset values to identify the currently executing statement in a batch

32. Diagnosing Performance with Wait Statistics
SOS_SCHEDULER_YIELD

33. Diagnosing Performance with Wait Statistics
SOS_SCHEDULER_YIELD
SOS: SQLOS

34. Diagnosing Performance with Wait Statistics
SOS_SCHEDULER_YIELD
SOS: SQLOS
SCHEDULER: manages worker threads onto CPU threads

35. Diagnosing Performance with Wait Statistics
SOS_SCHEDULER_YIELD
SOS: SQLOS
SCHEDULER: manages worker threads onto CPU threads
YIELD: Giving way to another

36. Diagnosing Performance with Wait Statistics
SOS_SCHEDULER_YIELD
SOS: SQLOS
SCHEDULER: manages worker threads onto CPU threads
YIELD: Giving way to another
Waiting for another worker thread to yield the CPU thread

37. Diagnosing Performance with Wait Statistics
PAGE_LATCH / PAGE_IO_LATCH

38. Diagnosing Performance with Wait Statistics
PAGE_LATCH / PAGE_IO_LATCH
PAGE: unit of data storage in SQL Server

39. Diagnosing Performance with Wait Statistics
PAGE_LATCH / PAGE_IO_LATCH
PAGE: unit of data storage in SQL Server
IO: reading (I) and writing (O), in this case disk IO

40. Diagnosing Performance with Wait Statistics
PAGE_LATCH / PAGE_IO_LATCH
PAGE: unit of data storage in SQL Server
IO: reading (I) and writing (O), in this case disk IO
LATCH: Lightweight locking mechanism

41. Diagnosing Performance with Wait Statistics
PAGE_LATCH / PAGE_IO_LATCH
PAGE: unit of data storage in SQL Server
IO: reading (I) and writing (O), in this case disk IO
LATCH: Lightweight locking mechanism
Waiting for a latch on a page in memory or a page on disk

42. Diagnosing Performance with Wait Statistics
CXPACKET

43. Diagnosing Performance with Wait Statistics
CXPACKET
CX: Communication eXchange

44. Diagnosing Performance with Wait Statistics
CXPACKET
CX: Communication eXchange
PACKET: unit of communication

45. Diagnosing Performance with Wait Statistics
CXPACKET
CX: Communication eXchange
PACKET: unit of communication
Parallelism is occurring

46. Diagnosing Performance with Wait Statistics
NETWORK_IO

47. Diagnosing Performance with Wait Statistics
NETWORK_IO
NETWORK: External communication

48. Diagnosing Performance with Wait Statistics
NETWORK_IO
NETWORK: External communication
IO: Reading (I) and writing (O)

49. Diagnosing Performance with Wait Statistics
NETWORK_IO
NETWORK: External communication
IO: Reading (I) and writing (O)
SQL is writing faster than the client is reading

50. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_xxxxx

51. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_xxxxx
PREEMPTIVE: Non-yielding

52. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_xxxxx
PREEMPTIVE: Non-yielding
OS: Operating System

53. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_xxxxx
PREEMPTIVE: Non-yielding
OS: Operating System
xxxxx: The OS operation or API being called
Non-yielding shell out to the Operating System

54. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_AUTHENTICATIONOPS

55. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_AUTHENTICATIONOPS
PREEMPTIVE: Non-yielding
OS: Operating System

56. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_AUTHENTICATIONOPS
PREEMPTIVE: Non-yielding
OS: Operating System
AUTHENTICATIONOPS: The OS operation or API being called

57. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_AUTHENTICATIONOPS
PREEMPTIVE: Non-yielding
OS: Operating System
AUTHENTICATIONOPS: The OS operation or API being called, a group of API calls related to authentication

58. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_AUTHENTICATIONOPS
PREEMPTIVE: Non-yielding
OS: Operating System
AUTHENTICATIONOPS: The OS operation or API being called, a group of API calls related to authentication
Non-yielding shell out to the OS to perform authentication operations

59. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_VERIFYSIGNATURE

60. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_VERIFYSIGNATURE
PREEMPTIVE: Non-yielding
OS: Operating System
VERIFYSIGNATURE: The OS operation or API being called

61. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_VERIFYSIGNATURE
PREEMPTIVE: Non-yielding
OS: Operating System
VERIFYSIGNATURE: The OS operation or API being called
Let’s Look it Up

62. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_VERIFYSIGNATURE
PREEMPTIVE: Non-yielding
OS: Operating System
VERIFYSIGNATURE: The OS operation or API being called
Verifies if a digital signature matches the signature used to encrypt data

63. Diagnosing Performance with Wait Statistics
PREEMPTIVE_OS_VERIFYSIGNATURE
PREEMPTIVE: Non-yielding
OS: Operating System
VERIFYSIGNATURE: The OS operation or API being called
Let’s Look it Up

64. Diagnosing Performance with Wait Statistics
Resources

65. Diagnosing Performance with Wait Statistics
Q & A

66. Thank you for coming! Thanks! My blog: www.sqlsoldier.com
Twitter: twitter.com/SQLSoldier
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