Worked on the apache/incubator-gluten repository to address a critical bug in the query engine’s handling of PartialMerge aggregate expressions. Focused on backend development and distributed systems, the work involved refining the rewriteAggregateExpression logic in Java and Scala to prevent extraction of expressions in Partial and Complete modes. This change stabilized the ProjectExecTransformer by eliminating invalid reference bindings, which previously led to incorrect query plans and runtime errors. The targeted fix improved the reliability and predictability of analytics workloads, reduced production failures, and demonstrated a deep understanding of query optimization, SQL semantics, and disciplined version control in a complex codebase.