By design, when connection pooling is used for a Spotfire Information Services data source (using the settings for Min and Max connections), the connections are kept open.  Unless it is considered broken, the connection is kept open until the connection pool is cleared, which happens when a data source is re-saved or the server is restarted. There can be as many inactive connections to a data source as the configured "Max connections" value for that data source. 

If you want each connection to close after use, disable the connection pooling by setting both "Max connections" and "Min connections" to 0 (zero) for that data source, and re-save the data source.

Note: When you re-save a Spotfire Information Services data source, you need to re-enter the database password that it uses in connecting to the target database.