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 

getFakePartCoveringAllPartsInPartition(partition_id, drop_range, delimiting_block_lock, true);
        String drop_range_fake_part_name = getPartNamePossiblyFake(format_version, drop_range);
        DataPartPtr covering_part;
        DataPartsVector src_all_parts;
        {
            
            auto parts_lock = src_data.lockParts();
            src_all_parts = src_data.getActivePartsToReplace(drop_range, drop_range_fake_part_name, covering_part, parts_lock);
        }
        if (covering_part)
            throw Exception(ErrorCodes::LOGICAL_ERROR, "Got part {} covering drop range {}, it's a bug",
                            covering_part->name, drop_range_fake_part_name);
        
        
        
        
        Coordination::Error version_check_code = zookeeper->trySet(alter_partition_version_path, "", alter_partition_version_stat.version);
        if (version_check_code != Coordination::Error::ZOK)
            throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER, "Cannot DROP PARTITION in {} after copying partition to {}, "
                            "because another ALTER PARTITION query was concurrently executed",
                            getStorageID().getFullTableName(), dest_table_storage->getStorageID().getFullTableName());
        DataPartsVector src_parts;
        MutableDataPartsVector dst_parts;
        Strings block_id_paths;
        Strings part_checksums;
        std::vector<EphemeralLockInZooKeeper> ephemeral_locks;
        LOG_DEBUG(log, "Cloning {} parts", src_all_parts.size());
        static const String TMP_PREFIX = "tmp_move_from_";
        
        String dest_alter_partition_version_path = dest_table_storage->zookeeper_path + "/alter_partition_version";