Statistics
https://play.clickhouse.com/play?user=play#c2VsZWN0IAp0b1N0YXJ0T2ZIb3VyKGNoZWNrX3N0YXJ0X3RpbWUpIGFzIGQsCmNvdW50KCksICBncm91cFVuaXFBcnJheShwdWxsX3JlcXVlc3RfbnVtYmVyKSwgIGFueShyZXBvcnRfdXJsKQpmcm9tIGNoZWNrcyB3aGVyZSAnMjAyMi0wNi0wMScgPD0gY2hlY2tfc3RhcnRfdGltZSBhbmQgdGVzdF9uYW1lIGxpa2UgJyUwMjQ5MV9wYXJ0X2xvZ19oYXNfdGFibGVfdXVpZCUnIGFuZCB0ZXN0X3N0YXR1cyBpbiAoJ0ZBSUwnLCAnRkxBS1knKSBncm91cCBieSBkIG9yZGVyIGJ5IGQgZGVzYw==

Some times there are not output from requests.
max_added_blocks);
        if (!query_info.merge_tree_select_result_ptr->error())
        {
            
            
            auto sum_marks = query_info.merge_tree_select_result_ptr->marks() + 1;
            if (sum_marks < min_sum_marks)
            {
                selected_candidate = nullptr;
                min_sum_marks = sum_marks;
            }
        }
        
        for (auto & candidate : candidates)
        {
            if (candidate.desc->type == ProjectionDescription::Type::Aggregate)
            {
                selectBestProjection(
                    reader,
                    storage_snapshot,
                    query_info,
                    added_filter_nodes,
                    analysis_result.required_columns,
                    candidate,
                    query_context,
                    max_added_blocks,
                    settings,
                    parts,
                    selected_candidate,
                    min_sum_marks);