presto-main/src/main/java/io/prestosql/execution/SqlStageExecution.java/SqlStageExecution/stateChanged
class SqlStageExecution:        @Override
        public void stateChanged(TaskStatus taskStatus)
        {
            try {
                updateMemoryUsage(taskStatus);
                updateCompletedDriverGroups(taskStatus);
            }
            finally {
                updateTaskStatus(taskStatus);
            }
        }