Why Does Discoverer Create Two Dedicated Connections?

A couple of people recently asked the question on the OTN Discoverer Forum:

"I am new to Discoverer tool as such. Therefore I have this question, pl pardon me if it very basic.

When I use the desktop edition of Discoverer to make a connection to the Oracle db. One the database side, it creates 2 dedicated connection for that Discoverer session. Is this normal, so something is not right in my environment configuration."

and

"I've recently started using Discoverer and I too have noticed this 'feature'.

I have a vanilla Discoverer 4.1 Client Installation on NT, without tweaking any of the defaults. I'm sure our DBA's would like to know why there are 2 sessions - and if this can be configured (i.e. reduced)."

The reason you have two dedicated connections is because Discoverer makes two connections to the database - one to the End User Layer tables, and one to the source database tables themselves.

This is mentioned in metalink note 62315.1 "SQL*Net Tracing Requirements for Discoverer".