SQL Server 2008 : SQL Server Agent (part 1) - Operators, Enabling SQL Server Agent Notifications & Alerts

1. Operators

The first thing you need to do is define an operator so you can receive automatic notifications through SQL Server Agent. An operator consists of two basic pieces of information: a name used to identify the operator and the contact information used to notify the operator. To add an operator using SQL Server Management Studio, expand SQL Server Agent in the Object Explorer, right-click the Operators folder, and select New Operator from the context menu. This will open the New Operator dialog box shown in Figure 1.

Figure 1. New Operator dialog box

Enter an operator name and email address, and click OK. Although you can configure net send and pager information, these options are deprecated and will be removed in a future version of SQL Server, so you should avoid using them. The only information you should enter here is the name of the operator and the email address that you will use to receive event notifications.

You can also add an operator using the sp_add_operator procedure located in the msdb. The following statement adds an operator named DBA Support and supplies an email address as the contact information.

EXEC msdb.dbo.sp_add_operator
     @name='DBA Support',
     @email_address='[email protected]'

2. Enabling SQL Server Agent Notifications

You have to enable the alert system in SQL Server Agent before you can start receiving notifications. Once you have configured Database Mail and added an operator, the next thing you should do is enable the alert system and designate a fail-safe operator. This is a designated operator that will receive notifications in the event that the primary operator is unreachable. In SQL Server Management Studio, right-click SQL Server Agent and select properties from the context menu. This will bring up the SQL Server Agent Properties dialog box. Select the Alert System page, as shown in Figure 2.

Figure 2. SQL Server Agent Properties dialog box Alert System page

There are only a few settings on this page you need to configure. Under the Mail Session section, select Enable Mail Profile. This will allow you to select the mail system and profile that SQL Server Agent will use to send notifications. You should select Database Mail from the Mail System drop-down list. SQL Mail is the other available mail system option; however, you should avoid SQL Mail because it will be removed in a future release. Now select the profile SQL Server Agent will use to send alert notifications from the Mail Profile drop-down list.

The next thing you need to do is select Enable Fail-Safe Operator under the Fail-Safe Operator section. Now you can select the operator from the drop-down list that you want to receive notifications in case the designated operator is unreachable. SQL Server stores the fail-safe operator information in the registry in case the operator tables in the msdb are unavailable. We are using an operator called DBA Support, as shown in Figure 13-10. You should then select the E-mail check box to specify that the fail-safe operator will receive notifications using email. Remember, you should avoid the Pager and Net Send options, since they will no longer be supported in a future release.

Select OK to close the SQL Server Agent Properties dialog box. You must restart SQL Server Agent before the new settings will take effect. You are now ready to start receiving automatic notifications from SQL Server Agent alerts and jobs.

3. Alerts

A SQL Server Agent alert is an automatic response to a predefined event. You can configure SQL Server Agent alerts to fire in response to SQL Server events, SQL Server performance counters, and Windows Management Instrumentation (WMI) events. Once an event has caused an alert to fire, you can respond to the alert by notifying operators of the event or even running a job after the event has occurred.

So, what kind of alerts should you have in place that will lead to proactive maintenance? At the very minimum, you should have a separate alert configured for fatal errors, which are indicated by severity codes 19 through 25. Let's walk through an example of creating an alert that will notify you of any fatal errors encountered with the severity of 19 called "Fatal Error in Resource." To add an alert using SQL Server Management Studio, expand SQL Server Agent in the Object Explorer, right-click the Alerts folder, and select New Alert from the context menu. This will open the New Alert dialog box shown in Figure 3.

Figure 3. New Alert dialog box General page

Give the alert a descriptive name and make sure the Enable check box is selected. We will call this alert "Fatal Error in Resource." Select SQL Server Event Alert from the Type dropdown list. The Event Alert Definition section will change depending on the type of alert you have selected. You can limit the alert to a specific database by selecting it from the Database name drop-down list; for this example, you should select <all databases>. We want to monitor errors with a severity of 19, so select the Severity option to enable the drop-down list, and then select 019 - Fatal Error in Resource. Select the Response page, as shown in Figure 4, to define the action that SQL Server Agent will perform when the event occurs.

Figure 4. New Alert dialog box Response page

The Response page allows you to perform two actions in response to an event: execute a job and notify an operator of the event. You can select an existing job to run from the Execute Job drop-down list, or select the New Job button to open the New Job dialog box and create a new job. If you choose a job from the drop-down list and select the View Job button, SQL Server will display the Job Properties dialog box that will allow you to view and edit an existing job.

All of the existing operators are displayed in the Operator List area. Check the E-mail column for each operator you would like to receive a notification email when the alert is triggered. Remember, the Pager and Net Send options are deprecated, so you should avoid these two options. You can select the New Operator button to open the New Operator dialog box, or select the View Operator button to open the Operator Properties dialog box for the selected operator. We have chosen to notify the DBA Support operator we created in the previous "Operators" section. Select the Options page, as shown in Figure 5, to make the final configurations to the new alert.

Figure 5. New Alert dialog box Options page

Select the E-mail check box at the top of the Options page so the error text for the event will be included in the email that the operator receives. The Additional Notification Message to Send text box will allow you to send further information or instructions along with the error text to the operator. You can use the Delay Between Responses section to suspend additional responses for the alert for a specified amount of time. Adding a delay between responses is useful for error messages that may occur in rapid succession; nobody wants to receive a hundred emails in five minutes. Click OK to close the New Alert dialog box and create the alert.

You can repeat this process for each alert you want to create on every SQL Server instance, or you can create a T-SQL script you can quickly run on all of your SQL Server instances. The code in Listing 1 will generate the same alert we just created for severity 19 using SQL Server Management Studio.

Example 1. Code to Create an Alert for Severity 19 Messages

USE msdb
GO
EXEC msdb.dbo.sp_add_alert
    @name=N'Fatal Error in Resource',
    @message_id=0,
    @severity=19,
    @enabled=1,
    @delay_between_responses=0,
    @include_event_description_in=1,
    @notification_message=N'This is a Fatal Alert. Please review immediately.'
GO

EXEC msdb.dbo.sp_add_notification
    @alert_name=N'Fatal Error in Resource',
    @operator_name=N'DBA Support',
    @notification_method = 1
GO

					  

You can also define an alert for a specific error number, regardless of the severity, by entering the exact error number. We have seen some specific blog entries around the need to create an alert for error 825, which deals with an IO issue. You can read more on error 825 on Paul Randal's blog located at http://sqlskills.com/BLOGS/PAUL/post/A-little-known-signof-impending-doom-error-825.aspx.

For a complete list of messages and their severity codes, you can query the sys.messages catalog view. There are far too many messages in the sys.messages catalog view to review each one manually. You can narrow down the messages by limiting the results by language and only showing the messages that SQL Server will log. You can also limit the results to messages with a severity of less than 19, as shown in the following query, since you should already be monitoring messages with a severity of 19 and above. You can review the list returned by the following query to determine if you want to add additional alerts for specific errors.

SELECT *
FROM sys.messages
WHERE language_id = 1033 and
            is_event_logged = 1 and
            severity < 19