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

Some times there are not output from requests.
}
        
        for (const String & col : partition_key_expr->getRequiredColumns())
            columns_alter_type_check_safe_for_partition.insert(col);
    }
    for (const auto & index : old_metadata.getSecondaryIndices())
    {
        for (const String & col : index.expression->getRequiredColumns())
            columns_alter_type_forbidden.insert(col);
    }
    if (old_metadata.hasSortingKey())
    {
        auto sorting_key_expr = old_metadata.getSortingKey().expression;
        for (const auto & action : sorting_key_expr->getActions())
        {
            for (const auto * child : action.node->children)
                columns_alter_type_forbidden.insert(child->result_name);
        }
        for (const String & col : sorting_key_expr->getRequiredColumns())
            columns_alter_type_metadata_only.insert(col);
        
        
    }
    if (!merging_params.sign_column.empty())
        columns_alter_type_forbidden.insert(merging_params.sign_column);
    
    NameSet columns_in_keys;
    columns_in_keys.insert(columns_alter_type_forbidden.begin(), columns_alter_type_forbidden.end());
    columns_in_keys.insert(columns_alter_type_metadata_only.begin(), columns_alter_type_metadata_only.end());
    columns_in_keys.insert(columns_alter_type_check_safe_for_partition.begin(), columns_alter_type_check_safe_for_partition.end());