Summary

File monitoring is a feature that helps content managers maintain maximum freshness of indexed content for local and network file sources. Coveo Enterprise Search monitors the Windows file system and updates the index in real time when files are added, modified or deleted. The following article describes the benefits of the File Monitoring feature, its usage and its limitations.

Benefits

Some sources contain documents that are updated on a regular basis. This makes index freshness a very important factor if you wish to keep relevance of the search results at a high level. File monitoring provides a way to ensure up-to-date indexes. When it is enabled for a source, the index is updated in real time as soon as files are created, modified or deleted from the file system. The only delay between the file modification and the index update is the time required to apply the transaction.

Coveo Enterprise Search's file monitoring feature is very flexible. It gives the content manager the high level of freshness required for many types of sources. File monitoring can be disabled for sources that contain more static data, or enabled for sources for which freshness is critical.

File Monitoring Enabling/Disabling

The File Monitoring feature is very useful. Therefore, it is automatically enabled when a Local/Network Files source is started. If file monitoring is not required for a specific source, it can be disabled by clicking on the Disable File Monitoring link.

Detected Events

The Microsoft Windows file system generates many types of events according to actions performed on files or folders. The file monitoring feature only catches events that are relevant to Coveo Enterprise Search. Here are the events caught by the file monitoring:

· File created

· File content modified

· File attribute modified

· File or folder deleted

· File or folder security modified

· File or folder copied or moved

· File or folder renamed

Limitations

Coveo Enterprise Search uses Windows events to monitor the file system. These events last a short persistent time. As a result, if a very large number of events occur at the same time, some of these events might be overlooked by the file monitor. Internal benchmarks demonstrated that the file monitor can handle approximately 4000 events per minute. Due to this limitation, it is recommended that you execute the Refresh Source option if the file system sustains an important volume of file events.

Furthermore, events can still be ignored even if file monitoring is enabled for a given source and the Coveo Enterprise Search service is started. Some of the program's states automatically disable file monitoring. Events are ignored when the system is in the following states:

· Indexing Disabled

· Read-only mode Enabled

· Index compaction

Another limitation occurs when an application (e.g. Microsoft Word, Microsoft Excel...) opens a file in exclusive mode. In this case, others applications are not able to open the file. It is therefore impossible to index its content. When this situation occurs, actions are queued and the File Monitor will try to update the file at regular intervals. Ultimately, the application will release the file and it will be indexed. However, if the Coveo Enterprise Search service is shut down before the application releases the file, queued events are lost. Hence, a source refresh is required to index the file modifications.

Last Reviewed	2006/04/03
Keywords	File monitoring, Windows events, File monitoring limitations