Question

To start off – I have 2 separate websites and a database (IIS 7.5, ASP.NET and SQL Server 2008, using Linq-To-SQL for database access).

I have a separate administrative website that sometimes, during usage needs to trigger long running operations (more than 10 seconds) on database. The problem is that those operations cause sqlserver process to hit 100% CPU and then other, main customer website, can’t access database promptly – there are some delays in accessing database.

I am OK with those administrative operations lasting 2x or 4x or nx times longer since they are lower priority.

I’ve tried using CPU Limit setting on AppPool in IIS, but that doesn’t help, as w3wp.exe process never uses much of CPU… rather it’s sqlservr.exe. Thanks in advance for your suggestions!

Answer 1

Sounds like you want to look into Resource Governor which is built into SQL server as of SQL 2008. BOL link should get you started.

http://msdn.microsoft.com/en-us/library/bb933866(v=SQL.100).aspx

Essentially, you can throttle CPU and memory usage for the resource pools and workloads you define. This throttling will only kick in when the server is under load. Be aware that you cannot control disk IO utilization. If the process in your admin database is IO bound and your other DBs share drives you will inevitably still see performance issues and moving databases to separate spindles or query tuning will be necessary.

Example of the classifier function that will ensure the user you define is throttled by the desired resource pool based on workload group:

/* Classifier function */
CREATE FUNCTION dbo.rgov_classifier_db ()
RETURNS sysname
WITH SCHEMABINDING
AS
BEGIN
    DECLARE @rgWorkloadGrp sysname
    IF SUSER_SNAME() = 'adminWebsiteDB'
        SET @rgWorkloadGrp = 'workloadGroupName'
    ELSE
        SET @rgWorkloadGrp = 'defaultWorkloadGroupName'
    RETURN @rgWorkloadGrp
END;
GO
/* Register the function with Resource Governor and then start Resource Governor. */
ALTER RESOURCE GOVERNOR
    WITH (CLASSIFIER_FUNCTION = dbo.rgov_classifier_db);
GO
ALTER RESOURCE GOVERNOR RECONFIGURE;
GO