Topic Last Modified: 2007-01-23

The Microsoft® Exchange Server Analyzer Tool uses the Exchange Server User Monitor (ExMon) tool to determine whether user MAPI operations are taking longer than should reasonably be expected on a healthy server that is running Exchange Server.

As part of its analysis, the Exchange Server Analyzer reviews the ExMon data for user-issued MAPI Restrict operations that have taken longer than 30 seconds to be completed.

The MAPI Restrict operation is used by client applications to select items that match particular criteria. The server creates a view that is, effectively, a table with associated criteria called a restriction. If the view that has a matching restriction already exists, the server uses the existing view to satisfy the user request. When the server uses this view, this is a less expensive operation than when the server creates a new view. By default, the store caches only 11 views for each folder. If the server is asked to create a twelfth view, it deletes the oldest cached view and creates a new view. Views add overhead to all actions on items.

If the Exchange Server Analyzer determines that a user-issued MAPI Restrict operation has taken longer than 30 seconds, the Exchange Server Analyzer displays an error.

MAPI Restrict operations that take longer than 30 seconds may not always be a problem. However, if the user or users experience frequent delays or delays that adversely affect their messaging experience, these delays may indicate that a user application is causing new views to be created.

To address this error, work with the user who is experiencing the high latency to determine the following:

• Whether the item counts in folders are high.
  
  
• What applications the user is running.
  
  

To address this issue, follow these steps:

• Encourage users who have many items in their folders to reduce the number of items per folder. It is recommended that you keep items in the Inbox, Calendar, Sent Items, Contacts and Deleted Items folders to fewer than 5,000.
  
  
• Configure the most operationally expensive client computers to use Cached Exchange Mode. Pay extra attention to client computers that have long latencies on Restrict, SetColumns or FindRow operations. Cached Exchange Mode isolates the server from most of the excess RPC traffic.
  
  
• Follow the guidance from the Exchange Team Blog referenced in the following section to turn on event log restriction tracing. Then turn on the user applications one by one to trace which application may be causing the long-running restriction.
  
  
• Try turning off all the applications. Then turn them on one by one to find which one might be causing the problem. Permanently turn off any problem applications or update them to reduce the load to an appropriate level if either of the following conditions is true:
  
  
  • The application is not required for business.
    
    
  • The application has a published update.
    
    

Also, you should be aware that when there is a bottleneck for resources, generally a disk or CPU bottleneck, the latencies for the Restrict operations will increase.

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