How to prevent toad disconnecting its session after some time?
See the Dell website:
Keeping database connections alive is generally not recommended
...
If you would still like to force connectivity at all times, you can do so by doing one of the following two suggestions.
A)
Turn ON the DBMS Output (Polling) in Toad, which is similar to Toad pinging the database. Go to the Editor Window | DBMS Output Tab (lower half of the Editor window) | click on the "Turn Output On" red icon | then the icon will turn green.
NOTE: Starting Toad version 12.1, it’s little different. Also ensure the “Interval Polling” button or icon is 'depressed' as that is the one that sends the polling at every i.e. 5 seconds. You can set this to 60 seconds, which is the max.
B)
Start Database | Monitor | Session Browser, which has an auto refresh feature, which should cause some activities to occur on the database.
NOTE: The Session Browser feature requires DBA privileges.
There is no straightforward way. One way to achieve this is to use the "Test connection(Reconnect)" option with a shortcut command.
Go to Session ---> Test Connections(Reconnect) and press enter.
You can map the above-mentioned command to an easy key combination so that it will be available for you whenever you get the disconnected error.
To map the shortcuts, Go to
View ---> Toad Options ---> Select "Shortcuts" in the available options. Find the TestConnections(Reconnect) command and assign new shortcuts keys you wanted.