**Describe the bug**

I have a table like:

```
CREATE TABLE test (
    time DateTime64(3)
    ...
) ENGINE = MergeTree()
PARTITION BY toStartOfInterval(time, INTERVAL 1 HOUR)
...
```

But when I search in `system.parts` it does not appear to have the `min/max` columns appropriately set?

```
partition:                             2020-06-01 01:00:00
min_date:                              1970-01-01
max_date:                              1970-01-01
min_time:                              1970-01-01 00:00:00
max_time:                              1970-01-01 00:00:00
```

I assume that if these were correctly set, doing a `select toStartOfInterval(time, interval 1 day), count()` type query would be pretty instant rather than trying to scan everything? I am guessing this is due to the `DateTime64` type in use?

Clickhouse 20.11.3.3

{
    bool prefixed = false;
    String id;
    if (format_version < MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
    {
        
        if (const auto * partition_lit = partition_ast->as<ASTPartition &>().value->as<ASTLiteral>())
        {
            id = partition_lit->value.getType() == Field::Types::UInt64
                 ? toString(partition_lit->value.get<UInt64>())
                 : partition_lit->value.safeGet<String>();
            prefixed = true;
        }
        else
            id = getPartitionIDFromQuery(partition_ast, context);
    }
    else
        id = getPartitionIDFromQuery(partition_ast, context);
    return [prefixed, id](const String & partition_id)
    {
        if (prefixed)
            return startsWith(partition_id, id);
        else
            return id == partition_id;
    };
}
PartitionCommandsResultInfo MergeTreeData::freezePartition(