public TSStatus dropTopic(DropTopicPlan plan) {
    acquireWriteLock();
    try {
      topicMetaKeeper.removeTopicMeta(plan.getTopicName());
      return new TSStatus(TSStatusCode.SUCCESS_STATUS.getStatusCode());
    } finally {
      releaseWriteLock();
    }
  }
Caller should ensure that the method is called in the lock {@link #acquireWriteLock}.
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/persistence/subscription/SubscriptionInfo.java