@Override
  public void readLock() {
    // apply read lock for SG insert lock to prevent inconsistent with concurrently writing memtable
    insertLock.readLock().lock();
    // apply read lock for TsFileResource list
    tsFileManager.readLock();
  }
lock the read lock of the insert lock
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/DataRegion.java