Hallam: SQL Server and SQL Managed Instance
enable you to ration or allocate
an instance's, critical resources,
so that more consistent performance is available
to databases in a multi application environment.
Resources are allocated by assigning them to resource pools,
incoming connections are assigned to a workload group.
Each workload group is assigned to a resource pool.
Initially, an instance has two resource pools:
Internal is for SQL Server's use,
while the default is, well the default,
for any connecting users or applications.
A resource pool can have limits specified
for CPU and memory usage.
Incoming connections are assigned to a workload group
by their username, via a classification function.
The classification function can be arbitrarily complex,
so long as it doesn't impede logging in,
and is selected from the classifier function name
dropdown list, in the resource governor properties page.
The resource governor is mostly used
in multi-tenant environments,
to ensure consistence performance
across customers' databases.
That is not to say it can't be utilized
in other scenarios to reduce the impact
of background tasks on mission critical systems.