Think about what happens when you issue a query to update a row:
*The optimizer creates an execution plan
*The query is executed
*The row will be read from disk into memory
*The update will be written to the transaction log
*The row will be changed in memory
*Confirmation will be sent back to the client
Imagine if you could measure the amount of time that was spent waiting for things within each of these stages. It probably won’t surprise you to hear that you can and not only is monitoring waits possible, but it can actually form a very effective part of a performance troubleshooting strategy.
Wait time is effectively dead time, and if you can reduce the amount of time you spend waiting, you’ll be able to achieve better overall performance. This session covers how SQL Server waits work, what types there are, and how to view and track them directly through DMV’s as well as using some of the most popular tools. It also covers common scenarios and their associated wait types. Because SQL Server waits represent just a single view of performance, you will also see when to correlate the results with system monitor counters.
Christian Bolton is the Technical Director for Coeo Ltd, a leading provider of SQL Server Managed Support and Consulting to organisations in the UK and Europe. Prior to this, Christian worked for 5 years as a Senior Premier Field Engineer for Microsoft UK working with some of Microsoft’s biggest customers. He is a Microsoft Certified Architect, Certified Master and MVP for SQL Server, and lead author of Professional SQL Server 2008 Internals and Troubleshooting. He works out of London and lives in the south of England with his wife and children and can be contacted through http://coeo.com.