public static File[] findCompactionLogs(CompactionTaskType type, File timePartitionDir) {
    if (timePartitionDir.exists()) {
      String logNameSuffix = getLogSuffix(type);
      return timePartitionDir.listFiles((dir, name) -> name.endsWith(logNameSuffix));
    } else {
      return new File[0];
    }
  }
MergeLogger records the progress of a merge in file "merge.log" as text lines.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/compaction/execute/utils/log/CompactionLogger.java