// Truncate the log files of this task-attempt so that only the last
// retainSize many bytes of this log file is retained and the log
// file is reduced in size saving disk space.
long retainSize =
(task.isMapTask() ? mapRetainSize : reduceRetainSize);
LogFileDetail newLogFileDetail = null;
try {
newLogFileDetail =
truncateALogFileOfAnAttempt(task.getTaskID(),
taskLogFileDetails.get(task).get(logName), retainSize,
tmpFileOutputStream, logFileInputStream, logName);