**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 :)

{
    return getMaxPartsCountForPartitionWithState(DataPartState::Active);
}
size_t MergeTreeData::getMaxInactivePartsCountForPartition() const
{
    return getMaxPartsCountForPartitionWithState(DataPartState::Outdated);
}
std::optional<Int64> MergeTreeData::getMinPartDataVersion() const
{
    auto lock = lockParts();
    std::optional<Int64> result;
    for (const auto & part : getDataPartsStateRange(DataPartState::Active))
    {
        if (!result || *result > part->info.getDataVersion())
            result = part->info.getDataVersion();
    }
    return result;
}
void MergeTreeData::delayInsertOrThrowIfNeeded(Poco::Event * until, ContextPtr query_context) const