What does "Polling caught an exception, restarting polling." error mean?

Question

We recently discovered the below error in our log which happened before our Reporting Services going down. Our servers have been very slow lately and wondering if this could be part of the problem.

Error Message: "Polling caught an exception, restarting polling. Error Message System.Data.SqlClient.SqlException: Timeout expired."

Answer 1

Polling is used to detect scheduled reports and subscriptions.

SQL Agent runs jobs (created by the subscription page) that populates tables that are polled every 10 secs by Rpt Svcs (defined in .config files, default is 10 IIRC).

Anyway, this means that the RS box could not query the RS database to see if anything happened.