**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 :)

{
    auto lock = lockParts();
    for (const auto & part : remove)
    {
        auto it_part = data_parts_by_info.find(part->info);
        if (it_part == data_parts_by_info.end())
            throw Exception("Part " + part->getNameWithState() + " not found in data_parts", ErrorCodes::LOGICAL_ERROR);
        assert(part->getState() == MergeTreeDataPartState::PreActive);
        modifyPartState(part, MergeTreeDataPartState::Temporary);
        
        data_parts_indexes.erase(it_part);
    }
}
void MergeTreeData::removePartsFromWorkingSet(
        MergeTreeTransaction * txn, const DataPartsVector & remove, bool clear_without_timeout, DataPartsLock * acquired_lock)
{
    auto lock = (acquired_lock) ? DataPartsLock() : lockParts();
    for (const auto & part : remove)
    {
        if (!data_parts_by_info.count(part->info))
            throw Exception("Part " + part->getNameWithState() + " not found in data_parts", ErrorCodes::LOGICAL_ERROR);
        part->assertState({DataPartState::PreActive, DataPartState::Active, DataPartState::Outdated});
    }
    removePartsFromWorkingSet(txn, remove, clear_without_timeout, lock);
}
void MergeTreeData::removePartsInRangeFromWorkingSet(MergeTreeTransaction * txn, const MergeTreePartInfo & drop_range, DataPartsLock & lock)