Execute some action when user terminate session

[Lorenzo Milesi]

Hi.

I need to perform several queries on radacct to make statistics about user connection, duration and so on.
Since executing some queries can be time consuming it's not advisable that I run them on the radius database, so I'm considering copying all or some informations from radacct somewhere else.
So, the question is: is it possible to perform some action when an user session is terminated? 
Or: is there any better solution which doesn't involve data duplication?

Thanks.