Improving ASP.NET Session State database performance by reducing blocking
On a recent consulting engagement, I was working with a client that had significant performance issues with their ASP.NET session state database. They had a combination of both large session state and a large number of concurrent sessions. They were regularly experiencing command timeouts on that database.

In my investigation, curiously I found that a DELETE statement was the culprit. I tracked it to the DeleteExpiredSessions stored procedure. Looking at it, it seems tame enough:

CREATE PROCEDURE DeleteExpiredSessions
AS
  DECLARE @now DATETIME
  SET @now = GETUTCDATE()

  DELETE ASPState..ASPStateTempSessions
  WHERE Expires < @now 

  RETURN 0

GO

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