Architecture for Dashboard in Web Application (Java based)

I have the requirement for building an Activity Dashboard for users when they log into the web application. The Dashboard will show various “portlets” of business transactions which have taken place since they last logged in, etc.

I was wondering what the ideal architecture for such a system should be? If the dashboard is to have 7-10 different portlets of data, should each portlet do a DB call on the specific individual table to get the latest transactions? Or should there be a common activity table where when a business transaction execute开发者_开发问答s it dumps data (who, what, where) into this common table (synchronous or via a messaging queue) and then this is the only table which is then queried by the dashboard?

Which solution would be better for high performance and scalability?

Thanks in advance for your input.

SP

Answer depends upon the number of events your application generate etc. But I'd go for a different activity table for different portlet and have proper indexes in place.