**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 :)

case PartitionCommand::ATTACH_PARTITION:
                current_command_results = attachPartition(command.partition, metadata_snapshot, command.part, query_context);
                break;
            case PartitionCommand::MOVE_PARTITION:
            {
                switch (*command.move_destination_type)
                {
                    case PartitionCommand::MoveDestinationType::DISK:
                        movePartitionToDisk(command.partition, command.move_destination_name, command.part, query_context);
                        break;
                    case PartitionCommand::MoveDestinationType::VOLUME:
                        movePartitionToVolume(command.partition, command.move_destination_name, command.part, query_context);
                        break;
                    case PartitionCommand::MoveDestinationType::TABLE:
                    {
                        String dest_database = query_context->resolveDatabase(command.to_database);
                        auto dest_storage = DatabaseCatalog::instance().getTable({dest_database, command.to_table}, query_context);
                        movePartitionToTable(dest_storage, command.partition, query_context);
                    }
                    break;
                    case PartitionCommand::MoveDestinationType::SHARD:
                    {
                        if (!getSettings()->part_moves_between_shards_enable)
                            throw Exception(ErrorCodes::SUPPORT_IS_DISABLED,
                                            "Moving parts between shards is experimental and work in progress"
                                            ", see part_moves_between_shards_enable setting");
                        movePartitionToShard(command.partition, command.part, command.move_destination_name, query_context);
                    }
                    break;
                }