Momentum Migration Fails on Validation

If the "heartbeat" from the upgrade conversion stops during
the validation phase (server.log file)
indicates "Validating row 18000/400000" or similar) then this
is the script to run as user TRIRIGA on the database:

UPDATE ENVIRONMENT_PROPERTIES SET VALUE = 'false' WHERE
ENVIRONMENT = 'SYSTEM' AND PROPERTY = 'LOCK';
COMMIT;

Then, if necessary, kill the java processes on app server (killall -KILL
java) and restart Jboss/weblogic instance; it will skip the
validation step and go on.