HOW IT WORKS: SQL Server Scheduler Affinity

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SQL Server uses 3 types of affinity to control where the SQL Server worker threads execute.  Before explaining the different scheduler affinity types let me clarify some terminology.


Node Types

SQL Server makes a specific distinction between scheduling and memory nodes.


Scheduling nodes:        sys.dm_os_nodes

Memory nodes:            sys.dm_os_memory_nodes


A scheduling node is a used to group a set of SQLOS schedulers.  The scheduling node must :

–       Remain within a single memory node.

–       Can be configured to use a subset of the CPUs presented by the OS from the