**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 :)

ColumnPtr & column = virtual_columns_block.safeGetByPosition(i).column;
        column = column->filter(*filter.data, -1);
    }
    size_t pos = 0;
    for (size_t i : metadata_snapshot->minmax_count_projection->partition_value_indices)
    {
        if (required_columns_set.contains(partition_minmax_count_column_names[pos]))
            for (const auto & part : real_parts)
                partition_minmax_count_columns[pos]->insert(part->partition.value[i]);
        ++pos;
    }
    size_t minmax_idx_size = real_parts.front()->minmax_idx->hyperrectangle.size();
    for (size_t i = 0; i < minmax_idx_size; ++i)
    {
        if (required_columns_set.contains(partition_minmax_count_column_names[pos]))
        {
            for (const auto & part : real_parts)
            {
                const auto & range = part->minmax_idx->hyperrectangle[i];
                auto & min_column = assert_cast<ColumnAggregateFunction &>(*partition_minmax_count_columns[pos]);
                insert(min_column, range.left);
            }
        }
        ++pos;
        if (required_columns_set.contains(partition_minmax_count_column_names[pos]))
        {
            for (const auto & part : real_parts)
            {
                const auto & range = part->minmax_idx->hyperrectangle[i];
                auto & max_column = assert_cast<ColumnAggregateFunction &>(*partition_minmax_count_columns[pos]);