Topic Last Modified: 2006-09-06
The Microsoft® Exchange Server Analyzer Tool includes a performance data collection engine that is used to query performance counter objects on computers that are running Exchange 2000 Server or Exchange Server 2003. The performance data collection engine collects data from the Cat: Categorizations in progress and the Categorizer Queue length performance counters of the SMTP Server performance object to analyze performance data.
The Cat: Categorizations in progress performance counter shows the number of categorizations in progress whereas the Categorizer Queue length performance counter shows the number of messages in the categorizer queue.
For this query, the Exchange Server Analyzer retrieves a sample every 6 seconds for a two-minute period. The Exchange Server Analyzer reports the average value for the performance counter during the collection interval.
The Exchange Server Analyzer examines the average number of categorizations in progress and compares that number against the number of categorizations still in the queue.
The Exchange Server Analyzer displays an error if, over the sample period, the following conditions are true:
- The average number of categorizations in progress is zero.
- The average categorizer queue length is more than zero.
The categorizer performs the following core operations:
- Resolves and validates all recipients.
- Determines limits and restrictions for all recipients.
- Expands distribution lists if that is required.
- Determines whether the message is for local or remote
This error indicates that there are messages stuck in the categorizer queue that have failed categorization with a retryable error.
Generally, messages accumulate in queues because the advanced queuing engine is unable to categorize the message. The advanced queuing engine may be unable to access the global catalog servers and access recipient information. Alternatively, the global catalog servers may be unreachable or performing slowly. In addition, messages can accumulate for the following reasons:
- The Active Directory® directory service is
Note: The categorizer uses Active Directory to categorize messages.
- Active Directory may be too heavily loaded if many
messages have queued in the pre-categorization queue.
- There is a failure in conversion. The categorizer also handles
- The message categorizer cannot find the mailbox stores.
- If Simple Mail Transfer Protocol (SMTP) was reinstalled or
removed, this may invalidate the following IIS metabase keys:
/smtpsvc/DsUseCat and /smtpsvc/vsi#/DsUseCat.
Note: Determine whether SMTP was reinstalled or removed.
You can examine the properties of the queue to determine the cause of the failure. For example, if the queue properties display a message that resembles "An SMTP error has occurred," you should review your server's event logs to locate any SMTP errors. If there are no events in the log, you should increase the SMTP logging level.
For more information about how to troubleshoot Exchange and SMTP queues, see the following Exchange resources:
- "Troubleshooting Mail Flow and SMTP" in the Exchange Server
Transport and Routing Guide (http://go.microsoft.com/fwlink/?LinkID=67875).
- Microsoft Knowledge Base article 823489, "How to use Queue
Viewer to troubleshoot mail flow issues in Exchange
Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=823489).
- Microsoft Knowledge Base article 821877, "Description of Fields
on the SMTP and X.400 Queue Properties Tabs" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=821877).
- Microsoft Knowledge Base article 264054, "XCON: Understanding
Queue States in Exchange 2000 Server" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=264054).
- "Troubleshooting Microsoft Exchange Server Performance"
- "Performance and Scalability Guide for Exchange Server 2003"
The message categorizer performance counters are published separately for each SMTP virtual server instance. For a list of the available performance counters related to the Message Categorizer, see Microsoft Knowledge Base article 231734, "XCON: Performance Monitor Counters for Message Categorizer" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=231734).