dd, the drawback of serializable reads is that attempting to make
transactions run this way kills application performance. Either the
sessions single thread or error off because Oracle is unable to
serialize the transaction.

The Oracle concurrency model was chosen to provide high concurrent data
access while providing time consistent views of the data. You need to
give consideration to the effect of concurrent access to the data
involved in all multistatement transactions. The fact that writers do
not block readers is very important in situation such as where you try
to use table triggers to enforce referential integrity rules rather
than FK.

HTH -- Mark D Powell --