multiple connects to database

How does reporting services handle connection strings. There is a single report using a shared datasource. Testing this report seems to generate multiple connections to the database for a single user. The report being tested has 4 datasets (3 to obtain parameter value lists) using the same shared datasource but the number of connections for the single user were 20 in one instance. When does reporting services make the connection and when does it release it? It didnt seem to let these go when the report was done executing. Using RS2005 sp1 with DB2The Report Server processes the dataset queries in parallel whenever possible. This is why you see three connections open when you run a report with multiple datasets. Not sure why the number of connections jump to 20. Does the DB2 provider support connection pooling?