public void mergeAll() throws StorageEngineException {
    if (CommonDescriptor.getInstance().getConfig().isReadOnly()) {
      throw new StorageEngineException("Current system mode is read only, does not support merge");
    }
    dataRegionMap.values().forEach(DataRegion::compact);
  }
merge all databases.

@throws StorageEngineException StorageEngineException
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/StorageEngine.java