How fast is my Transactional replication throughout the day?

If you want to test the speed of your Transactional replication there is a neat functionality called Tracer Tokens. This will tell you how quick is it to get a record from the publisher to the distributor and from there to the subscriber. In the old days you’d have to create a dummy table to do all this but since SQL 2005 it’s out of the box :).

To add a tracer token use the replication monitor and edit the Transactional publication as below:

Basically, a token is written to the transaction log of the publisher. This is treated as a normal replicated command, and passes from the transaction log to the distribution database and then is ‘run’ by the distribution agent.

You’ll see the various latency times recorded for each subscription. If you have a distribution agent set to work on a schedule (i.e. not running continuously) you’ll see the following sort of scenario until the distribution agent runs.

To add one programatically for reporting purposes just roll the following type of script:

DECLARE @myTokenID AS int
EXEC sp_posttracertoken
@publication = ‘YourPubName’,
@tracer_token_id = @myTokenID OUTPUT;
select @myTokenID 

Trapping the TokenID is actually optional but is very useful if you want to check on the resulting latencies for this particular token. So,

EXEC sp_helptracertokenhistory
@publication = ‘YourPubName’,
@tracer_id = -2147483641 

where -2147483641 is the ID of the tracer token.


Or just roll your own report based on;

select * from distribution..MStracer_tokens

This way you can create a custom alert so the support team know when there is an issue. There are SQL Agent alerts based on the Log Reader Agent and Distribution Agents which can be configured, but the method above is a little more under our control and can be used for reporting purposes. This way you can add a Tracer Token every 10 minutes and plot performance over the course of a day.

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