I am reading clickhouse mutation code. In StorageMergeTree->selectPartsToMutate() function, there is a check 
`if (current_ast_elements + commands_size >= max_ast_elements)
                break;`

I think if there are many mutations then the check result will be true, so that it will skip the remaining mutations.
But the new part's mutation is set to the last one in mutation map, and it does not apply the remaining mutations actually.
`new_part_info.mutation = current_mutations_by_version.rbegin()->first;`

Then the new part will miss the remaining mutations in future mutation job.

I think it's wrong here. Am I right?

If it is right, I will submit a PR 

original_active_part->force_keep_shared_data = true;
            }
            modifyPartState(original_active_part, DataPartState::DeleteOnDestroy);
            data_parts_indexes.erase(active_part_it);
            auto part_it = data_parts_indexes.insert(part_copy).first;
            modifyPartState(part_it, DataPartState::Committed);
            removePartContributionToDataVolume(original_active_part);
            addPartContributionToDataVolume(part_copy);
            auto disk = original_active_part->volume->getDisk();
            String marker_path = fs::path(original_active_part->getFullRelativePath()) / IMergeTreeDataPart::DELETE_ON_DESTROY_MARKER_FILE_NAME;
            try
            {
                disk->createFile(marker_path);
            }
            catch (Poco::Exception & e)
            {
                LOG_ERROR(log, "{} (while creating DeleteOnDestroy marker: {})", e.what(), backQuote(fullPath(disk, marker_path)));
            }
            return;
        }
    }
    throw Exception("Cannot swap part '" + part_copy->name + "', no such active part.", ErrorCodes::NO_SUCH_DATA_PART);
}
MergeTreeData::DataPartPtr MergeTreeData::getActiveContainingPart(const MergeTreePartInfo & part_info) const
{
    auto lock = lockParts();
    return getActiveContainingPart(part_info, DataPartState::Committed, lock);
}
MergeTreeData::DataPartPtr MergeTreeData::getActiveContainingPart(const String & part_name) const