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 

MatcherFn matcher,
    const StorageMetadataPtr & metadata_snapshot,
    const String & with_name,
    ContextPtr local_context)
{
    String clickhouse_path = fs::canonical(local_context->getPath());
    String default_shadow_path = fs::path(clickhouse_path) / "shadow/";
    fs::create_directories(default_shadow_path);
    auto increment = Increment(fs::path(default_shadow_path) / "increment.txt").get(true);
    const String shadow_path = "shadow/";
    /
    const auto data_parts = getDataParts();
    String backup_name = (!with_name.empty() ? escapeForFileName(with_name) : toString(increment));
    String backup_path = fs::path(shadow_path) / backup_name / "";
    for (const auto & disk : getStoragePolicy()->getDisks())
        disk->onFreeze(backup_path);
    PartitionCommandsResultInfo result;
    size_t parts_processed = 0;
    for (const auto & part : data_parts)
    {
        if (!matcher(part->info.partition_id))
            continue;
        LOG_DEBUG(log, "Freezing part {} snapshot will be placed at {}", part->name, backup_path);
        part->volume->getDisk()->createDirectories(backup_path);
        String src_part_path = part->getFullRelativePath();
        String backup_part_path = fs::path(backup_path) / relative_data_path / part->relative_path;