what happens if a failed transaction is not rolled back?

Hi All,

i understand when writing application code, we should rollback a
transaction that fails to commit. this is typically done in the catch block
of a try-catch exception handler. but what if the developer does not
rollback the transaction? what happens in that case?

note that i am not asking: what happens if a transaction is not rolled back?
i am asking: what happens if a *failed* transaction is not rolled back?

failed transaction = you try to commit it but get an exception back from
the database.

thanks.

S.