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It is important to differentiate between Waits and Queues , when applying the Waits and Queues performance analysis methodology. Even though they are two sides of the same problem , they are approaching resource usage in a different manner.
Waits , refers to any time spent waiting on resources by any given session .
Queues, is a reference to PERFMON counters and various other Resource usage information .
Perfmon analysis focuses on Queues . Refering to a previous post – Query Response Time , a query is comprised of 3 aspects:
1)CPU (Running) = One session can be executing, per scheduler
2)Wait time (suspended) = The session is waiting for an event to complete to complete e.g Async_IO_completion
3)Signal Wait time (Runnable Queue Time) = The session is waiting for CPU
Examples of PERFMON counters :
In Contrast ,waits refers to any time spent waiting on resources by the session
Examples of Wait Types :
One troubleshooting approach is to identify initial problems with Wait Stats and then correlate with PERFMON information
Source:Jack Vamvas (http://www.sqlserver-dba.com)
Author: Jack Vamvas (http://www.sqlserver-dba.com)
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