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

Some times there are not output from requests.
const MergeTreeDataSelectExecutor & reader,
    const StorageSnapshotPtr & storage_snapshot,
    const SelectQueryInfo & query_info,
    const ActionDAGNodes & added_filter_nodes,
    const Names & required_columns,
    ProjectionCandidate & candidate,
    ContextPtr query_context,
    std::shared_ptr<PartitionIdToMaxBlock> max_added_blocks,
    const Settings & settings,
    const MergeTreeData::DataPartsVector & parts,
    ProjectionCandidate *& selected_candidate,
    size_t & min_sum_marks)
{
    MergeTreeData::DataPartsVector projection_parts;
    MergeTreeData::DataPartsVector normal_parts;
    for (const auto & part : parts)
    {
        const auto & projections = part->getProjectionParts();