Xiaolong Guo developed the Map Aggregation Feature (map_agg) for Trino within the pinterest/starrocks repository, enabling aggregation of key-value pairs into map structures for more expressive analytics queries. Working primarily in Java, Xiaolong focused on backend development and unit testing to ensure robust integration of the new Trino function. The implementation expanded the API surface for user-defined functions and supported richer business intelligence workflows by allowing map value aggregation in Trino queries. Over the course of the month, Xiaolong demonstrated effective repository collaboration and code review practices, delivering a focused feature that aligns with StarRocks’ roadmap for advanced data aggregation.