2. Agenda Parallel Processing Concepts Single Query Optimization
Workload Optimization 3. Parallel ProcessingHow does it Work ? 4.
Preemptive Scheduling Thread 1 CMD CMDCore Scheduler CMD Thread 2
CMD CMD CMD Thread 3 CMD CMDContext Switch CMD 5. How does it work
in SQL Server Thread Pool(Workers)Tasks BatchCPU Core SELECT
TaskRead .. Read ..Write UPDATE .Calculate .WritePending Tasks
Scheduler Max Workers !! 6. CPU Scheduling Runnable QueueSuspended
(Waiting) TasksCPU CoreIO_COMPLETIONRead LCK_M_XCalculateWrite
Scheduler Running Task - Worker Pending TasksReadWrite 7. Now you
own theParallelism Matrix ! 8. What about the1 Million Dollar
Question ? 9. What degree of parallelism (DOP) is optimal ? 10.
Parallel System Configuration MAXDOP Cost Threshold for Parallelism
Max Workers 11. Parallel System Configuration MAXDOP Cost Threshold
for Parallelism Max Workers 12. MaxDop Default Microsoft
Recommendation Other Recommendations: Start with Cores / 3 - Cores
/ 2 and check CXPACKET 13. MaxDop What people
do?http://www.sqlskills.com/BLOGS/PAUL/post/MAXDOP-configuration-survey-results.aspx
14. Waits What people
have?http://www.sqlskills.com/BLOGS/PAUL/post/Wait-statistics-or-please-tell-me-where-it-hurts.aspx
15. MaxDop Its only a hint, SQL Server might still choosea serial
plan Change of MAXDOP setting for theserver, will flush the plan
cache. 16. Parallel System Configuration MAXDOP Cost Threshold for
Parallelism Max Workers 17. Cost Threshold for Parallelism Default
(5) Other Recommendations: 5 is too low, Get it higher to
50Jonathan Kehayias Recommendation 18. My RecommendationIt really
depends on your workload, you needto first test:For OLTP have
Higher Cost Threshold (50) Start with low MAXDOP (8-12)For OLAP
have Higher Cost Threshold (50) Start with high MAXDOP (Cores / 2)
19. My RecommendationsRun Jonathan Kehayias Script to tune
CostThreshold for Parallelism.Run a trace, change MAXDOP, rerun a
traceon the same workload and run QureAnalyzer (Free !) until you
find the perfectMAXDOP.Override MAXDOP if necessary (Use
PlanGuides): In OLTP override with a higher MAXDOP. In OLAP
override with a lower MAXDOP. 20. Become a true Pro !Join one of
our courses: SQL Server 2012 Guy Glantser Storage for DBAs Tzahi
Hakikat Advanced Programming in SQL Server Noam BrezisContact Us:
www.madeira.co.il 21. Thank youTo: Guy Glantser (Madeira) Haim
Fishner (Madeira) Adam Machanic R Meyyappan
(http://www.sqlworkshops.com/)Contact Us: www.madeira.co.il 22.
Thank You! Noam Brezis
Email:[email protected]:www.madeira.co.il
