message: feat: clear query cache only when updates really happen
diff: @@ -1497,9 +1497,12 @@ Database::query(const string _query, ResultSet& _result_set, FILE* _fp)
  general_evaluation.releaseResult();
  delete[] update_triple;
  - //TODO: maybe no updates are really done!
  + //NOTICE: maybe no updates are really done!
  + if(success_num > 0)
  + {
  this->query_cache->clear();
  cout<<"QueryCache cleared"<<endl;
  + }
  pthread_rwlock_unlock(&(this->update_lock));
  }
  