Presentation used for the "SQL Server Scheduling Basics" session at the SQL Bangalore UG Meeting on July 13th, 2013.

1. Amit Banerjee
Senior PFE
Microsoft Corporation
SQL Server Scheduling
Basics

2. About Me
Amit Banerjee
• Senior Premier Field Engineer, Bangalore, India
• 7+ years with Microsoft
• Formerly with SQL Server CSS Escalation Services
• Technology expertise: Databases (SQL Server), Debugging
Highlights:
• Owner of www.TroubleshootingSQL.com
• Speaker at various SQL community events
• Co-author of Professional SQL Server 2012: Internals and
Troubleshooting
• Guest Author for SQL Server World Wide Users Group (SSWUG)
Contact Information
Blog: www.troubleshootingsql.com
Twitter: @banerjeeamit
Twitter: @TblshootingSQL
Email: troubleshootingsql@outlook.com
Facebook: www.facebook.com/TroubleshootingSQL

3. 7/13/2013 3
WHY?
We wanted to write
more code!!
We didn’t know
Windows did
scheduling!!

4. 7/13/2013 4
ACTUALLY
Avoid thread context
switches as much as
possible
Support async I/O
Support fibers
Avoid causing kernel
mode wherever
possible

5. QUEUE
7/13/2013 5

6. MORE
QUEUES
7/13/2013 6

7. AND ….
7/13/2013 7

8. SQL OS
7/13/2013 8
Scheduling
I/O
Completion
Memory
management
Resource
Management

9. Max Worker
Threads
7/13/2013 9
MIND IT!!

10. Max
Worker
Threads
7/13/2013 10
For a 32-bit operating system:
Total available logical CPUs <= 4
Max Worker Threads = 256
Total available logical CPUs > 4
Max Worker Threads = 256 + ((logical CPUs -
4)*8)
For a 64-bit operating system:
Total available logical CPUs <= 4
Max Worker Threads = 512
Total available logical CPUs > 4
Max Worker Threads = 512 + ((logical CPUs -
4)*16)

11. QUEUES
7/13/2013 11
Timer List
I/O ListWaiter List
Runnable List

12. Runnable
List
7/13/2013 12
Bhaag worker thread… Bhaag

13. DEMO
7/13/2013 13
Some workers worker
threads were hurt
during the preparation
of this demo!!

14. Resources
7/13/2013 14
UMS Scheduler
http://msdn.microsoft.com/en-us/library/aa175393(v=SQL.80).aspx
SQL OS DMVs
http://msdn.microsoft.com/en-us/library/ms176083.aspx
Slava’s Blog
http://blogs.msdn.com/b/slavao/archive/2005/07/20/441058.aspx
Professional SQL Server 2012: Internals and Troubleshooting
Available on Flipkart and Amazon

15. © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista 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
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