Brad’s Sure Guide to SQL Server Maintenance Plans- P13 ppt

The Databases drop-down box appears on the configuration screen for all tasks that can be configured through the Wizard, with the exception of the Execute SQL Server Agent Job Chapter 1

Figure 3.8: The Define Database Check Integrity task configuration screen.

The basic layout of this screen is more or less the same for every task

• Database Selection – a drop-down box to choose the database(s) on which the task will

execute This step is common to most tasks

• Task-specific configuration options – a set of configuration options specific to a

given task

• Task Scheduling – an option to schedule the task This step is common to every

task, assuming that you chose Separate schedules for each task when you first

started the Wizard

Although this screen looks simple, it is hiding a lot of detail Let's take a look at each of the

Database Selection

As you might expect, the first step when configuring most tasks is to specify the database or databases on which the maintenance task to act The Databases drop-down box appears on

the configuration screen for all tasks that can be configured through the Wizard, with the exception of the Execute SQL Server Agent Job (Chapter 10), History CleanUp (Chapter 11) and Maintenance Cleanup (Chapter 15) tasks, where database selection is not necessary

In other cases, the database selection process for a task (for example the Rebuild Index task, see Chapter 7) is slightly more complex, as you will be offered the chance to narrow the scope

of the task to specific objects within a selected database However, most often you will want a task to act on the database as a whole

For all tasks where database selection is relevant, most of the other options on the screen will

be grayed out until you select at least one database

Figure 3.9: The database selection drop-down box.

So let's take a close look at how you use this option, as a lot of it is hidden away from us at the moment To select which databases you want to run this task against, click on the <Select one

or more> drop-down box, and the screen shown in Figure 3.10 appears This screen allows us

to make one selection from four different choices

All databases

This option means exactly what it says If you select this option, every database on your SQL Server instance will have the task run against it One advantage of using this option is that

it covers both user and system databases and, if you add any databases at any time, even after the Maintenance Plan has been created and is in production, they will automatically be included when this task runs As such, this option allows you to create a single Maintenance Plan to cover all of your databases

On the other hand, if you include all your databases in a single Maintenance Plan, you have less flexibility This means that, although selecting this option may seem to be the best choice,

it may not actually be the best, because you may need to treat some databases differently from others We will be talking more about this later in the book

Figure 3.10: The Maintenance Plan Wizard needs to know which databases you want to

run the task against.

System databases

This option specifies that your task will only run against the SQL Server instance's system databases, which include master, model, and msdb (but not tempdb)

out On the other hand, most production databases use the Full Recovery model, which allows transaction log backups to be made This and other differences between system and production database maintenance, mean it is common to create separate Maintenance Plans for each class of databases

tempdb and Maintenance Plans

tempdb is not included in a Maintenance Plan because it is automatically deleted and

recreated every time SQL Server is restarted.

All user databases

Just as a DBA often wants to create a Maintenance Plan that is specific to system databases,

so he or she will often create a plan dedicated to the maintenance of all production user databases A nice feature of this option is that it will automatically include all user databases, even ones that you create after the Maintenance Plan is created This is handy because you don't have to worry about modifying the Maintenance Plan if you subsequently add or delete databases from your SQL Server This is the option that we'll use for most of the examples in this book, as shown in Figure 3.10

These databases

This final option allows you to build a custom list of databases, both user and system, to which your task will apply This option is often used when you want to treat a particular database differently from the rest of the databases For example, you may have a policy that, for databases under a given size, the Rebuild Index task is used, but that the Reorganize Index and the Update Statistics tasks are preferred on any databases above that size This distinction is sometimes made if the Rebuild Index task on a large database takes longer to execute than the available maintenance window, which could end up blocking users trying

to access the database As we will learn later in this book, the Reorganize Index and the Update Statistics tasks, combined, perform a similar function to the Rebuild Index task, but do so without blocking users

A disadvantage of this option is that the databases you select here aren't dynamic By this, I mean that databases that are created or deleted subsequent to the creation of the plan are not automatically added to, or removed from, that plan In the latter case, this will mean that an error will occur when the Maintenance Plan is run You have to manually edit the Maintenance Plan every time you want to add or delete a database to be used by the plan

Ignore databases where the state is not online

Finally, on this screen is an Ignore databases where the state is not online checkbox which,

by default, is activated This means that any databases that are offline at the time when the plan is running will be ignored If you uncheck this box, and a maintenance task attempts

to run against an offline database, then the Maintenance Plan will fail when it is executed because it will not be able to complete its operation

Generally speaking, I suggest you leave this option activated to ensure that the plan works successfully on all online databases

Ignore databases where the state is not online…

…is only available in SQL Server 2008 If you run a SQL Server 2005 Maintenance Plan, and it includes tasks to be run against an offline database, then the Maintenance Plan will fail.

Task-Specific Configuration Options

Click on OK to be returned to the Define Database Check Integrity Task screen, with the

database choice displayed in the drop-down box, as shown in Figure 3.11