public void logSourceFiles(List<TsFileResource> sourceFiles) throws IOException {
    logFiles(sourceFiles, STR_SOURCE_FILES);
  }
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/SimpleCompactionLogger.java