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 

else
    {
        for (const DataPartPtr & part : parts_to_remove)
        {
            LOG_DEBUG(log, "Removing part from filesystem {}", part->name);
            part->remove();
        }
    }
}
size_t MergeTreeData::clearOldWriteAheadLogs()
{
    DataPartsVector parts = getDataPartsVector();
    std::vector<std::pair<Int64, Int64>> all_block_numbers_on_disk;
    std::vector<std::pair<Int64, Int64>> block_numbers_on_disk;
    for (const auto & part : parts)
        if (part->isStoredOnDisk())
            all_block_numbers_on_disk.emplace_back(part->info.min_block, part->info.max_block);
    if (all_block_numbers_on_disk.empty())
        return 0;
    std::sort(all_block_numbers_on_disk.begin(), all_block_numbers_on_disk.end());
    block_numbers_on_disk.push_back(all_block_numbers_on_disk[0]);
    for (size_t i = 1; i < all_block_numbers_on_disk.size(); ++i)
    {
        if (all_block_numbers_on_disk[i].first == all_block_numbers_on_disk[i - 1].second + 1)
            block_numbers_on_disk.back().second = all_block_numbers_on_disk[i].second;
        else
            block_numbers_on_disk.push_back(all_block_numbers_on_disk[i]);
    }
    auto is_range_on_disk = [&block_numbers_on_disk](Int64 min_block, Int64 max_block)
    {