Friday, June 6, 2008


On versions of SQL Server before 9.0.3171.0, a known issue can degrade query performance on 32-bit and 64-bit systems with 2 gigabytes (GB) or more of memory. When you execute queries under the context of a login that is not a member of the sysadmin fixed server role, you might encounter performance degradation symptoms that arise from a large and growing Security Token cache. These issues can include performance degradation of queries, high CPU usage for the SQL Server process, and a sharp increase in worker threads and SQL user connections. Systems that have less than 2 GB of memory should not experience these issues because normal memory usage requirements keep the Security Token cache from growing too large.


  1. A large number of users running queries on the SQL instance and intermittently you find that the duration of queries increases intermittently
  2. Most of the queries in the environment exhibit this pattern for random parameters and not any specific query/proc with any specific parameter
  3. DBCC MEMORYSTATUS output for the SQL instance shows that the memory usage for SQL is gradually increasing over a period of time
  4. High CPU during the problem period
  5. DBCC FREEPROCCACHE or DBCC FREESYSTEMCACHE fixes the issue temporarily

Related Articles

  • KB article 927396: Queries take a longer time to finish running when the size of the TokenAndPermUserStore cache grows in SQL Server 2005
  • KB article 933564: FIX: A gradual increase in memory consumption for the USERSTORE_TOKENPERM cache store occurs in SQL Server 2005
  • KB article 937745: FIX: You may receive error messages when you try to log in to an instance of SQL Server 2005 and SQL Server handles many concurrent connections
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