16 April 2013

Data not yet sent to the mirror

by Grant Fritchey

This metric tracks the amount of data waiting to be sent from the principal database to the mirror. This is known as the send queue.

Install metric...

Metrics install automatically if you have Redgate Monitor installed.

If you are using Redgate’s SQL Server monitoring tool, Redgate Monitor, you can instantly install and run this metric on your servers.

This metric is described in Grant Fritchey’s Custom Metrics for monitoring mirroring article on Simple Talk.

Use this metric to track the amount of data waiting to be sent from the principal database to the mirror. This is also known as the send queue. For more details, see Database Mirroring Sessions (MSDN article).

Important setup information

Before you can start using this metric, you need to:

Run the following Microsoft procedure on the msdb database you’ll use in the custom metric:
[sql]USE msdb;
GO
EXEC sp_dbmmonitoraddmonitoring;
GO
[/sql]This sets up a SQL Agent job that periodically updates information about the mirrored databases on your server. For more information, see http://msdn.microsoft.com/en-us/library/ms403582.aspx.
Make sure the SQL Agent is configured and running on the server. Then you can retrieve information using the sp_dbmmonitorresults procedure.

Metric definition

Name

Data not yet sent to mirror 'InsertDatabaseNameHere'

Description

This metric measures the amount of data (in KBs) waiting to be sent from the principal database to the mirror. This is also known as the send queue.

The T-SQL query that will collect data


		
			
			
Transact-SQL
			
			DECLARE	@MonitorResults AS TABLE (
	database_name VARCHAR(255),
	role INT,
	mirror_state TINYINT,
	witness_status TINYINT,
	log_generat_rate INT,
	unsent_log INT,
	sent_rate INT,
	unrestored_log INT,
	recovery_rate INT,
	transaction_delay INT,
	transaction_per_sec INT,
	average_delay INT,
	time_recorded DATETIME,
	time_behind DATETIME,
	local_time DATETIME);
 
INSERT	INTO @MonitorResults
		EXEC sp_dbmmonitorresults 
			@database_name = 'InsertDatabaseNameHere',
			@mode = 0,
			@update_table = 0;
 
SELECT	unsent_log
FROM	@MonitorResults;
			
				
					
				
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						DECLARE	@MonitorResults AS TABLE (
	database_name VARCHAR(255),
	role INT,
	mirror_state TINYINT,
	witness_status TINYINT,
	log_generat_rate INT,
	unsent_log INT,
	sent_rate INT,
	unrestored_log INT,
	recovery_rate INT,
	transaction_delay INT,
	transaction_per_sec INT,
	average_delay INT,
	time_recorded DATETIME,
	time_behind DATETIME,
	local_time DATETIME);
 
INSERT	INTO @MonitorResults
		EXEC sp_dbmmonitorresults 
			@database_name = 'InsertDatabaseNameHere',
			@mode = 0,
			@update_table = 0;
 
SELECT	unsent_log
FROM	@MonitorResults;

Instances to collect from

Select all

Databases to collect from

msdb

Collection frequency

Use collected or calculated values

Leave the Use a calculated rate of change between collections check box unchecked

Metric collection

Enabled

Alert definition

If you wanted to add an alert, track the metric values over time to determine sensible high, medium and low thresholds in your mirroring environment.

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Data not yet sent to the mirror

Metric definition

Name

Description

The T-SQL query that will collect data

Instances to collect from

Databases to collect from

Collection frequency

Use collected or calculated values

Metric collection

Alert definition

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