multi_del
删除多条数据
///
/// \brief multi_del
/// delete multiple value by key from the cluster.
/// \param hashkey
/// used to decide which partition to get this k-v
/// \param sortkeys
/// all the k-v under hashkey will be sorted by sortkey. should not be empty.
/// \param deleted_count
/// return count of deleted k-v pairs.
/// \param timeout_milliseconds
/// if wait longer than this value, will return time out error
/// \return
/// int, the error indicates whether or not the operation is succeeded.
/// this error can be converted to a string using get_error_string().
///
virtual int multi_del(const std::string &hashkey,
const std::set<std::string> &sortkeys,
int64_t &deleted_count,
int timeout_milliseconds = 5000,
internal_info *info = NULL) = 0;