public DataRegion loadSnapshotForStateMachine() {
    LOGGER.info(
        "Loading snapshot for {}-{}, source directory is {}",
        storageGroupName,
        dataRegionId,
        snapshotPath);

    File snapshotLogFile = getSnapshotLogFile();

    if (snapshotLogFile == null) {
      return loadSnapshotWithoutLog();
    } else {
      return loadSnapshotWithLog(snapshotLogFile);
    }
  }
1. Clear origin data 2. Move snapshot data to data dir 3. Load data region

@return
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/snapshot/SnapshotLoader.java