SQL> set timing on serveroutput on
SQL>
SQL> DECLARE
  2  V_EXISTS date;
  3  V_ROWID CHAR(18);
  4  begin
  5           FOR i in (......)
  6      LOOP
  7        SELECT ..................;
  8        select ......into .....;
  9      END LOOP;
 10      EXCEPTION
 11        WHEN OTHERS .........;
 12      END;
 13      /
ERROR:
ORA-03114: not connected to ORACLE


DECLARE
*
ERROR at line 1:
ORA-03135: connection lost contact
Process ID: 79678
Session ID: 629 Serial number: 14145


Elapsed: 00:30:00.67
SQL>

INBOUND_CONNECT_TIMEOUT_LISTENERNAME = 0

# This file is actually generated by netca. But if customers choose to 
# install "Software Only", this file wont exist and without the native 
# authentication, they will not be able to connect to the database on NT.

SQLNET.RECV_TIMEOUT = 0

SQLNET.AUTHENTICATION_SERVICES= (NTS)

SQLNET.EXPIRE_TIME = 0

SQLNET.SEND_TIMEOUT = 0

SQLNET.INBOUND_CONNECT_TIMEOUT = 0