HOW IT WORKS: SQL Server Scheduler Affinity


Moved from: bobsql.com

 

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