Your SlideShare is downloading. ×
0
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
What are you waiting for
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

What are you waiting for

225

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
225
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
5
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. What Are You Waiting For? Performing Wait Stat Analysis
  • 2. IntroductionJason e: jstrate@pragmaticworks.comStrate e: jasonstrate@gmail.com b: www.jasonstrate.com t: StrateSQLResources jasonstrate.com/go/Waits MAKING BUSINESS INTELLIGENT www.pragmaticworks.com
  • 3. What Are You Waiting For?You…• SQL Server• Developers• DBAs
  • 4. AgendaDefining Collecting Viewing Reviewing
  • 5. AgendaDefining Collecting Viewing Reviewing
  • 6. Wait, wait… I’ll Tell YouWaits: Resource waits occur when a workerrequests access to a resource that is notavailable because the resource is being used bysome other worker or is not yet available.
  • 7. So What?!
  • 8. Wait Statistics IdentityPrioritize Measure
  • 9. Execution Model (Simplified)Grocery Store• Cashier – Scheduler• Customer – Query• Checkout Line – Queue • Running • Runnable • Suspended
  • 10. Execution Model (Simplified) RUNNING
  • 11. Execution Model (Simplified) RUNNABLE RUNNING
  • 12. Execution Model (Simplified) RUNNABLE RUNNING WAIT SUSPENDED
  • 13. Execution Model (Simplified) RUNNABLE RUNNING SUSPENDED
  • 14. Execution Model (Simplified) RUNNABLE RUNNINGWAIT TIME SUSPENDED
  • 15. Execution Model (Simplified) RUNNABLE RUNNING SUSPENDED
  • 16. Execution Model (Simplified) RUNNABLE RUNNING SUSPENDED
  • 17. Execution Model (Simplified) RUNNABLE RUNNINGSIGNAL WAIT SUSPENDED TIME
  • 18. Agenda-ingDefining Collecting Viewing Reviewing
  • 19. Wait DMVs• sys.dm_os_wait_stats – Accumulated statistics on tasks that have waited for resources• sys.dm_os_waiting_tasks – Information on queued tasks waiting for resources
  • 20. Waits Stats
  • 21. Waits Stats Name of the wait type.
  • 22. Waits StatsNumber of waits on this wait type. This counter is incremented at the start of each wait.
  • 23. Waits StatsTotal wait time for this wait type in milliseconds. This time is inclusive of signal_wait_time_ms.
  • 24. Waits StatsMaximum wait time on this wait type.
  • 25. Waits StatsDifference between the time that the waiting thread was signaled and when it started running.
  • 26. Waiting Tasks
  • 27. Waiting Tasks
  • 28. Waiting TasksID of the session associated with the task.
  • 29. Waiting TasksTotal wait time for this wait type, in milliseconds. This time is inclusive of signal_wait_time.
  • 30. Waiting Tasks Name of the wait type.
  • 31. Waiting TasksID of the session that is blocking the request. If this column is NULL, the request is not blocked, or the session information of the blocking session is not available
  • 32. Waiting TasksDifference between the time that the waiting thread was signaled and when it started running.
  • 33. DemoVIEWING WAIT STATS
  • 34. AgendaDefining Collecting Viewing Reviewing
  • 35. DMV Stats
  • 36. Management Data Warehouse
  • 37. Do-It-YourselfCollect Summarize Analyze
  • 38. DemoDO-IT-YOURSELF
  • 39. AgendaDefining Collecting Viewing Reviewing
  • 40. Wait Types• Tied to process – Audit – Buffer – I/O – Indexing – Lock – SQLOS• Categories – Background – External – Queue
  • 41. Background WaitsCLR_SEMAPHORE CHECKPOINT_QUEUELAZYWRITER_SLEEP XE_TIMER_EVENTRESOURCE_QUEUE BROKER_TO_FLUSHSLEEP_TASKNot all inclusive BROKER_TASK_STOPSLEEP_SYSTEMTASK CLR_MANUAL_EVENTWAITFOR CLR_AUTO_EVENTLOGMGR_QUEUE XE_DISPATCHER_WAIT
  • 42. CXPACKETTranslation• Contention with queries the at are executing in parallel; across multiple CPUs. Generally due to unbalanced execution across CPUs or tasks ahead of query executing longer than expected.Guideline• >5% for OLTP• >10% for data warehousesResolution• Review indexing• Tune queries• Adjust Max Degree of parallelism• Research cost threshold for parallelism
  • 43. OLEDBTranslation• Occurs when SQL Server calls the Microsoft SQL Native Client OLE DB Provider. It indicates the duration of calls to the OLE DB provider.Guideline• Examine when it is a top wait and exceeds background waits. (TOP 5)Resolution• Identify queries with OLE DB waits with extended events or sys.dm_os_waiting_tasks• Check application placement and Disk secs/Read and Disk secs/Write• Tune transactions using RPC, Distributed (Linked Server), and Full Text Search
  • 44. PAGEIOLATCH_xTranslation• Contention caused by disk to memory transfer. Typically suggests disk IO subsystem issues.Guideline• Examine when it is a top wait and exceeds background waits. (TOP 5)Resolution• Review Physical disk: disk seconds/read and Physical disk: disk seconds/write and SQL Server Buffer Manager: Page Life Expectancy• Review information for virtual file stats• Reconfigure disk to improve IO throughput• Analyze indexes to reduce need to move data to memory• Increase memory to increase data available to SQL Server
  • 45. PAGELATCH_xTranslation• Contention between short term light weight synchronization objects. Latches are not held for the duration of a transaction. Occur in the buffer pool but unrelated to IO requests.Guideline• Examine when it is a top wait and exceeds background waits. (TOP 5)Resolution• Check tempdb configuration • Additional data files • Trace Flag 1118• Troubleshoot memory pressure
  • 46. LATCH_xTranslation• Contention between short term light weight synchronization objects. Latches are not held for the duration of a transaction. Non buffer pool related.Guideline• Examine when it is a top wait and exceeds background waits. (TOP 5)Resolution• Review T-SQL generating LATCH waits using extended events.• Examine memory items in sys.dm_os_latch_stats• Partition table across multiple files
  • 47. Additional Resources Waits and Queues • http://is.gd/qWGGnd SQLServerPedia • http://is.gd/gvD80N SQL Server Wait Type • http://is.gd/r59976 Repository Wait Stats Introductory • http://is.gd/khsduZ References Joe Sack • http://is.gd/dQWFwC • http://is.gd/VlH71lManagement Data Warehouse • http://is.gd/xggZSA DMVstats • http://sqldmvstats.codeplex.com
  • 48. For more information… Name: Jason Strate Email: jstrate@pragmaticworks.com Blog: www.jasonstrate.com Resource: jasonstrate.com/go/waits Products Services FoundationBI products to covert to a Microsoft BI Speed development through training, and Helping those who do not have theplatform and simplify development on rapid development services from means to get into information technologythe platform. Pragmatic Works. achieve their dreams.

×