And waits for them. That's pointless.
String containing_part = active_parts_set.getContainingPart(missing_part);
                if (!containing_part.empty())
                    parts_to_fetch.push_back(containing_part);
                else
                    LOG_WARNING(log, "Part {} on replica {} has been vanished.", missing_part, best_replica_path);
            }
        }
        LOG_INFO(log, "Parts to fetch: {}", parts_to_fetch.size());
        missing_parts.clear();
        for (const String & part : parts_to_fetch)
        {
            bool fetched = false;
            try
            {
                fetched = fetchPart(part, metadata_snapshot, best_replica_path, true, 0, zookeeper);
            }
            catch (const DB::Exception & e)
            {
                if (e.code() != ErrorCodes::RECEIVED_ERROR_FROM_REMOTE_IO_SERVER && e.code() != ErrorCodes::RECEIVED_ERROR_TOO_MANY_REQUESTS
                    && e.code() != ErrorCodes::CANNOT_READ_ALL_DATA)
                    throw;
                LOG_INFO(log, e.displayText());
            }
            if (!fetched)
                missing_parts.push_back(part);
        }
        ++try_no;
    } while (!missing_parts.empty());
}
void StorageReplicatedMergeTree::mutate(const MutationCommands & commands, ContextPtr query_context)