Change Tracking in SQL Server Full Text Search


By:   |   Updated: 2006-12-26   |   Comments   |   Related: More > Full Text Search


Problem

Creation and maintenance of full-text catalogs and indexes in SQL Server 2000 can be taxing on both the server and the administrator, as well as take a lot of time to populate. This can result in increased deployment times and potentially inaccurate search results. To ease the deployment process and increase the uptime of your application, you can use Change-Tracking population.

Solution

In the traditional methods of full-text catalog population, you can choose a full or incremental population. In full population, the catalog is "built from scratch", building an index entry for each row in the table. In incremental population, a timestamp is used to determine where to start the population. The sysfulltextnotify table holds entries for updated rows and is polled by the MSSearch service. You can handle when this table is polled in one of three ways:

Method Description T-SQL Statement
Scheduled Runs on whatever schedule you choose. Can be run via a SQL Agent job sp_fulltext_table table_name 'Start_change_tracking'

sp_fulltext_table table_name 'update_index'
On demand Runs whenever you run the statements. Changes are stored in the sysfulltextnotify table sp_fulltext_table table_name 'Start_change_tracking'

sp_fulltext_table table_name 'update_index'
Background Changes to the table rows are propogated when they occur sp_fulltext_table table_name 'Start_change_tracking'

sp_fulltext_table table_name 'start_background_updateindex'

The background population offers a couple of benefits:

  • Decreased time in propagating changes to the full-text catalog
  • A wider distribution of resource usage, since changes are made when the update occurs instead of having to apply the changes all at once

Once the population method is changed to change tracking, an incremental population begins to make sure the catalog is up to date. The only downside to switching to change tracking population is that entries are no longer written to the Event Log; however, you can devise another method for comparing the entries in the table with the number of rows in the full-text catalog to ensure the process is working for you.

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MSSQLTips author Edgewood Solutions Edgewood Solutions is a technology company focused on Microsoft SQL Server and founder of MSSQLTips.com.

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Article Last Updated: 2006-12-26

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