ORA 603 - cheeyoung/sqlplus-public GitHub Wiki
ORA-00603: ORACLE server session terminated by fatal error
Cause: An Oracle server session was in an unrecoverable state.
Action: Log in to Oracle again so a new server session will be created automatically. Examine the session trace file for more information.
ORA-00609: could not attach to incoming connection
Cause: Oracle process could not answer incoming connection
Action: If the situation described in the next error on the stack can be corrected, do so; otherwise contact Oracle Support.