TAILIEUCHUNG - Brad’s Sure Guide to SQL Server Maintenance Plans- P27

Brad’s Sure Guide to SQL Server Maintenance Plans- P27: SQL Server has a reputation as being a simple database application to install, configure, and maintain. This is a little misleading. SQL Server is a powerful relational database that can handle the needs of the largest organizations and, as such, its proper maintenance almost certainly requires the attention of an experienced DBA. | Chapter 9 Update Statistics Task Configuring the Update Statistics Task Now that we know what the Update Statistics task does let s learn how to configure it. The Define Update Statistics Task screen in the Maintenance Plan Wizard is shown in Figure . Figure The Update Statistics Task screen has both familiar and unfamiliar configuration options. The first part of the Define Update Statistics Task screen looks similar to the Rebuild Index Task and the Reorganize Index Task screens. 131 Chapter 9 Update Statistics Task Database Selection The options here with the Databases Object and Selection drop-down boxes are the same as those described in the equivalent section of Rebuild Index chapter Chapter 7 so 1 will not explain them again here. On the whole 1 recommend you don t use the Object and Selection options for this task. 1f you need this kind of granularity in your Maintenance Plan then you should be using T-SQL or PowerShell scripts instead. 1f you are using the Reorganize Index task as part of your Maintenance Plan then you should select the same databases here as you selected for the Reorganize Index task. As discussed previously any database that is reorganized needs to have its statistics updated. 1f you are creating a special Maintenance Plan that will only run the Update Statistics task for example on the days that you aren t running the Reorganize Index task or the Rebuild Index task then you will most likely want to select all your user databases. Once you have selected your databases the Update and Scan type options become available as shown in Figure . Let s take a look at each option in turn. The Update Option The Update option allows you to specify which types of statistics are to be updated. The options are fairly self-explanatory. All existing statistics - both column and index statistics are updated. Column statistics only - only updates column statistics. Index statistics only - only updates index statistics. The default is All existing

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