DDL Triggers & WMI Alerts

Kobi Cohen System DBA Manager

Spiral Solutions

Objectives

Implementing DDL Triggers.Implementing WMI Alerts.

ScopeAll server.

Database.

Fire in response to Data Definition Language (DDL).Create, Alter, Drop.

DDL event group (BOL).

For monitoring or preventing changes in the database.

Run only after T-SQL statement is completed.Cannot be used as INSTEAD OF triggers.

Do not create the inserted and deleted tables.Subsequent changes captured by EVENTDATA functionC:\Program Files\Microsoft SQL Server\100\Tools\Binn\schemas\sqlserver\2006\11\events\ orhttp://schemas.microsoft.com/sqlserver/

Generate XML data captured by XQuery.

DDL Triggers

Demo

Response to SQL Server eventsError message / error severity

Performance monitor counters

WMI events

Alert typesSQL Server event alert

SQL Server performance alert

WMI event alert

PermissionSysadmin server role

SQLAgentOperatorRole database role in msdb

Create alert – sp_add_alert in msdb

Drop Alert – sp_delete_alert in msdb

Get server alerts info – sp_help_alert in msdb

Alerts

WMI – Windows Management InstrumentationTurning SQL Server into a managed WMI object

Classes of properties and methods related to the system environment that you can access like a database

Raise alerts after WMI events occurrenceServer Events Classes (BOL)

Create WMI AlertWMI namespace to query for events

Default Instance – \\.\root\Microsoft\SqlServer\ServerEvents\MSSQLSERVER

Named Instance – \\.\root\Microsoft\SqlServer\ServerEvents\<Instance Name>

WMI Query Language (WQL) – Subset of structured query language (SQL) with WMI-specific extensions

Used to control the WMI Service

WMI Provider for Server Events translates the query into an event notification – service broker must be enabled on msdb.

WMI Alerts

SQL Agent registry parameters KEY_LOCAL_MACHINE\Software\Microsoft\Microsoft SQL Server\MSSQL.x\SQLServerAgent

EventWMILimit – how many events to consume every time it checks the WMI event queue (default to 5).

EventWMIPeekInterval – how often to look for WMI events (default to 30).

Adding DWORD registry entry alertAllowWMIRemoteEvents set to 1 and restart SQL Agent service (not supported).

WMI TokensFrom SQL Server 2005 changed from [X] to $(X) to avoid conflicts with database objects.

Allows users to send the info from a WMI event.

Strings in job step commands are parsed and replaced at run time.

Using SQL Server Agent Escape Macros (BOL).

WMI Alerts

Demo

Thanks