Last week i was doing a bit search in terms of connection pooling behavior. Hence i wanted to set the counters related to connection pooling.
Initially i set all the counters from the '.Net CLR Data' category. and at the end i was surprised that, it was not capturing anything. Then i did some more investigation and found that those counters are only for .Net 1.0 and 1.1 and Microsoft kept those set of counters for backward compatability.
For ADO.NET 2.0 those counters wont work, and MS added a new set of counters under '.Net Data provider for SQLServer' - for SQL server and '.Net Data provider for Oracle' - for Oracle database.
Hence be proactive, before setting the counters related to connection pool.
More detailed information about this you can find at
I hope this helps!.