private boolean loadCompactionThreadCountHotModifiedProps(TrimProperties properties)
      throws IOException {
    int newConfigCompactionThreadCount =
        Integer.parseInt(
            properties.getProperty(
                "compaction_thread_count",
                ConfigurationFileUtils.getConfigurationDefaultValue("compaction_thread_count")));
    if (newConfigCompactionThreadCount <= 0) {
      newConfigCompactionThreadCount = 1;
    }
    if (newConfigCompactionThreadCount == conf.getCompactionThreadCount()) {
      return false;
    }
    conf.setCompactionThreadCount(
        Integer.parseInt(
            properties.getProperty(
                "compaction_thread_count",
                ConfigurationFileUtils.getConfigurationDefaultValue("compaction_thread_count"))));
    return true;
  }
load a property file and set TsfileDBConfig variables.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/IoTDBDescriptor.java