Wait Stats

David Alcock provides an introduction to wait stats and why they’re useful for performance tuning:

So here are two different ways that we can use SQL Servers wait statistics for troubleshooting purposes. Both views give us really useful information but both have different purposes. If we wanted to look back over time then the sys.dm_os_wait_stats will give us a view of wait time totals. Typically we would capture the information via a scheduled job and analyse the data for spikes during periods where issues might be suspected.

For performing real-time analysis of wait statistics then we should base queries on the sys.dm_os_waiting_tasks view where we can see accurate wait duration values as they are happening within our instance.

In my opinion wait statistics are the most important piece of information when troubleshooting SQL Server so learning about the different types is vital for anyone using SQL. Thankfully there is a wealth of really useful information about wait statistics out there; I’ve listed some of my favourite posts below.

Click through for an example, as well as links to more resources.

Related Posts

Powershell Speed Testing

Shane O’Neill shows off a Powershell script which allows you to simplify performance testing: Apart from catching up on news during my commute I only really use notifications for a certain number of hashtags i.e. #SqlServer, #tsql2sday, #sqlhelp, and #PowerShell. So during work, every so often a little notification will pop up on the bottom […]

Read More

Legacy Cardinality Estimation In SQL Server

Kellyn Pot’vin-Gorman explains what the Legacy Cardinality Estimation setting does in SQL Server: Oracle DBAs have used the CARDINALITY hint for some time and it should be understood that this may appear to be similar, but is actually quite different.  As hinting in TSQL is a bit different than PL/SQL, we can compare similar queries […]

Read More

Categories

November 2016
MTWTFSS
« Oct Dec »
 123456
78910111213
14151617181920
21222324252627
282930