Database recently upgraded to version 11.2.0.2 and since then Toad has loses the session connection for no reason.
After losing the connection, it is necessary to reconnect to get the session back.
There is a bug with Oracle database 11.2.0.2 patch 10098816
This issue also occurs in SQL*Plus
Downgrade to a lower version of the Oracle client (10g or 9i)
