**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 :)

{
    NamesAndTypesList partition_key_columns;
    if (!partition_key.column_names.empty())
        partition_key_columns = partition_key.expression->getRequiredColumnsWithTypes();
    return std::make_shared<ExpressionActions>(std::make_shared<ActionsDAG>(partition_key_columns), settings);
}
Names MergeTreeData::getMinMaxColumnsNames(const KeyDescription & partition_key)
{
    if (!partition_key.column_names.empty())
        return partition_key.expression->getRequiredColumns();
    return {};
}
DataTypes MergeTreeData::getMinMaxColumnsTypes(const KeyDescription & partition_key)
{
    if (!partition_key.column_names.empty())
        return partition_key.expression->getRequiredColumnsWithTypes().getTypes();
    return {};
}
ExpressionActionsPtr MergeTreeData::getPrimaryKeyAndSkipIndicesExpression(const StorageMetadataPtr & metadata_snapshot) const
{
    return getCombinedIndicesExpression(metadata_snapshot->getPrimaryKey(), metadata_snapshot->getSecondaryIndices(), metadata_snapshot->getColumns(), getContext());
}
ExpressionActionsPtr MergeTreeData::getSortingKeyAndSkipIndicesExpression(const StorageMetadataPtr & metadata_snapshot) const
{
    return getCombinedIndicesExpression(metadata_snapshot->getSortingKey(), metadata_snapshot->getSecondaryIndices(), metadata_snapshot->getColumns(), getContext());
}
void MergeTreeData::checkPartitionKeyAndInitMinMax(const KeyDescription & new_partition_key)