In the Schema Browser, when selecting a table on a Peoplesoft (very large) database, my user has a very slow (30 minutes) response time before any information gets in the Right Hand Side window (columns, data, constraints, etc.). This only happens when connected to an Oracle 11g database.
The problem was related to the new 11g memory management feature i.e. AMM (Automatic Memory Management).
AMM was allocating 70% of the available memory for the Shared Pool letting only 6% for the buffer cache.
That was the reason for the huge physical reads.
Follow the steps below to configure some Optimizer hints in the Toad options to speed up the query.