UDA-SQL-0564 [Microsoft SQL Server Native Client 10.0]Communication link failure

Problem:

Each time you need to restart your database server, there is a chance you will get this error when trying to run a report based on that database: UDA-SQL-0564 [Microsoft SQL Server Native Client 10.0]Communication link failure.
It seems cognos does not refresh the data source status on every report request you make. So even if the database is already operational, all reports that fetch data from the database fail with the error in topic.

Solution:

One solution is to restart the cognos service, and this is what I have found when searching through the web. That works, true, but imho its a bit overkill to restart whole service and interrupt all running reports/jobs etc.
Second solution that works for me (Cognos 10.2) is to refresh report service connections:
Go to Administration, then System.
From scorecard pane, select System/Refresh report service connections. Voila. Simple as that.