core/src/main/java/com/orientechnologies/orient/core/storage/impl/local/statistic/OSessionStoragePerformanceStatistic.java
public void stopWALRecordTimer(boolean isStartRecord, boolean isStopRecord) {
    final long endTs = nanoTimer.getNano();
    final long timeDiff = (endTs - timeStamps.pop());

    if (walCountersHolder == null)
      walCountersHolder = new WALCountersHolder();

    walCountersHolder.logRecordCount++;
    walCountersHolder.logRecordTime += timeDiff;

    if (isStartRecord) {
      walCountersHolder.startRecordCount++;
      walCountersHolder.startRecordTime += timeDiff;
    } else if (isStopRecord) {
      walCountersHolder.stopRecordCount++;
      walCountersHolder.stopRecordTime += timeDiff;
    }

    makeSnapshotIfNeeded(endTs);
  }
public void stopWALRecordTimer(boolean isStartRecord, boolean isStopRecord) {
    final long endTs = nanoTimer.getNano();
    final long timeDiff = (endTs - timeStamps.pop());

    if (walCountersHolder == null)
      walCountersHolder = new WALCountersHolder();

    walCountersHolder.logRecordCount++;
    walCountersHolder.logRecordTime += timeDiff;

    if (isStartRecord) {
      walCountersHolder.startRecordCount++;
      walCountersHolder.startRecordTime += timeDiff;
    } else if (isStopRecord) {
      walCountersHolder.stopRecordCount++;
      walCountersHolder.stopRecordTime += timeDiff;
    }

    makeSnapshotIfNeeded(endTs);
  }
Stops and records results of timer which counts how much time was spent on logging of single write ahead log record.

@param isStartRecord Indicates whether we logged "start atomic operation" record
@param isStopRecord  Indicates whether we logged "stop atomic operation" record