Update Statistics Task (Maintenance Plan)

Use the Update Statistics Task dialog box to update SQL Server information about the data in the tables and indexes. This task resamples the distribution statistics of each index created on user tables in the database. The distribution statistics are used by SQL Server to optimize navigation through tables during the processing of Transact-SQL statements. To build the distribution statistics automatically, SQL Server periodically samples the data in the corresponding table for each index. This size of the sample is based on the number of rows in the table and the frequency of data modification. Use this option to perform an additional sampling using the specified percentage of data in the tables. SQL Server uses this information to create better query plans.

This task executes the UPDATE STATISTICS statement.

Options

• Connection
  Select the server connection to use when performing this task.

• New
  Create a new server connection to use when performing this task. The New Connection dialog box is described below.

• Databases
  Specify the databases affected by this task.

  • All databases
    Generate a maintenance plan that runs maintenance tasks against all SQL Server databases, except tempdb.
  • All system databases
    Generate a maintenance plan that runs maintenance tasks against each of the SQL Server system databases except tempdb. No maintenance tasks are run against user-created databases.
  • All user databases
    Generate a maintenance plan that runs maintenance tasks against all user-created databases. No maintenance tasks are run against the SQL Server system databases.
  • These specific databases
    Generate a maintenance plan that runs maintenance tasks against only those databases that are selected. At least one database in the list must be selected if this option is chosen.

  Note

  Maintenance plans only run against databases set to compatibility level 80 or higher. Databases set to compatibility level 70 or lower are not displayed.

• Object
  Limit the Selection grid to display tables, views, or both.

• Selection
  Specify the tables or indexes affected by this task. Not available when Tables and Views is selected in the Object box.

• All existing statistics
  Update statistics for both columns and indexes.

• Column statistics only
  Only update column statistics.

• Index statistics only
  Only update index statistics.

• Scan type
  Type of scan used to gather updated statistics.

• Full scan
  Read all rows in the table or view to gather the statistics.

• Sample by
  Specify the percentage of the table or indexed view, or the number of rows to sample when collecting statistics for larger tables or views.

• View T-SQL
  View the Transact-SQL statements performed against the server for this task, based on the selected options.

  Note

  When the number of objects affected is large, this display can take a considerable amount of time.

New Connection Dialog Box

• Connection name
  Enter a name for the new connection.

• Select or enter a server name
  Select a server to connect to when performing this task.

• Refresh
  Refresh the list of available servers.

• Enter information to log on to the server
  Specify how to authenticate against the server.

• Use Windows integrated security
  Connect to an instance of the SQL Server Database Engine with Windows Authentication.

• Use a specific user name and password
  Connect to an instance of the SQL Server Database Engine using SQL Server Authentication. This option is not available.

• User name
  Provide a SQL Server login to use when authenticating. This option is not available.

• Password
  Provide a password to use when authenticating. This option is not available.

See Also

Other Resources

UPDATE STATISTICS (Transact-SQL)

Help and Information

Getting SQL Server 2005 Assistance

Change History