**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 :)

{
    if (!getSettings()->remove_empty_parts)
        return 0;
    size_t cleared_count = 0;
    auto parts = getDataPartsVectorForInternalUsage();
    for (const auto & part : parts)
    {
        if (part->rows_count != 0)
            continue;
        
        if (!part->version.getCreationTID().isPrehistoric() && !part->version.isVisible(TransactionLog::instance().getLatestSnapshot()))
            continue;
        LOG_TRACE(log, "Will drop empty part {}", part->name);
        dropPartNoWaitNoThrow(part->name);
        ++cleared_count;
    }
    return cleared_count;
}
void MergeTreeData::rename(const String & new_table_path, const StorageID & new_table_id)