Friday, September 24, 2010

BIOS settings for Virtualization

This is not directly related to SQL Server, but this configuration would be needed for SQL Server Virtualization as well. Windows Server 2008 R2 comes with the built-in feature called Hyper-V to support for virtualization, meaning to manage virtual machines.

There are couple of configuration settings you need to enable in order to use Virtualization.

Saturday, September 18, 2010

Does SPID unique in sys.sysprocesses?

Sys.sysprocesses contains connection information for each connection made to the SQL Server. As you see it, it looks like SPID is unique. But actual it is not, because of KPID. KPID is Windows thread id. Each SQL Server task is assigned a Windows thread. SQL Server task is the unit of execution for SQL Server. The queries submitted to SQL Server may have parallel tasks like parallelism operator. In this case, SPID has several KPIDs, which duplicate SPID in the sys.sysprocesses view.

How to interpret Disk Latency

I was analyzing IO stats in one of our SQL Servers and noticed that IO latency (Read / Write) are very high. As a rule of thumb, we know tha...