**Describe the bug**

Since we upgraded to 20.10.3.30, one of our clickhouse cluster takes much more time to start. (Up to 50 minutes, and before it took ~3 minutes)
The log file is filled with
>  <Debug> DiskLocal: Reserving 1.00 MiB on disk `default`, having unreserved 16.90 TiB

Additionally, the memory consumption increases, linearly, a lot (up to arround 230 G for us) and then drop back to normal values once clickhouse finished starting up. During that loading phase, a single CPU core is used at 100%.
If that memory is not available for the machine, clickhouse gets OOMed by the kernel.


**How to reproduce**
* Issue appeared after we upgraded to ClickHouse server version 20.10.3.30

* How could I find wich of our tables may be responsible for that ?


**Expected behavior**
A fast startup :)

else
        partition_id = getPartitionIDFromQuery(partition, local_context);
    DataPartsVector parts;
    if (moving_part)
    {
        auto part_info = MergeTreePartInfo::fromPartName(partition_id, format_version);
        parts.push_back(getActiveContainingPart(part_info));
        if (!parts.back() || parts.back()->name != part_info.getPartName())
            throw Exception("Part " + partition_id + " is not exists or not active", ErrorCodes::NO_SUCH_DATA_PART);
    }
    else
        parts = getVisibleDataPartsVectorInPartition(local_context, partition_id);
    auto disk = getStoragePolicy()->getDiskByName(name);
    std::erase_if(parts, [&](auto part_ptr)
        {
            return part_ptr->data_part_storage->getDiskName() == disk->getName();
        });
    if (parts.empty())
    {
        String no_parts_to_move_message;
        if (moving_part)
            no_parts_to_move_message = "Part '" + partition_id + "' is already on disk '" + disk->getName() + "'";
        else
            no_parts_to_move_message = "All parts of partition '" + partition_id + "' are already on disk '" + disk->getName() + "'";
        throw Exception(no_parts_to_move_message, ErrorCodes::UNKNOWN_DISK);
    }
    if (!movePartsToSpace(parts, std::static_pointer_cast<Space>(disk)))
        throw Exception("Cannot move parts because moves are manually disabled", ErrorCodes::ABORTED);
}
void MergeTreeData::movePartitionToVolume(const ASTPtr & partition, const String & name, bool moving_part, ContextPtr local_context)