Worked on the pola-rs/polars repository to enhance CSV schema inference by introducing Int128 support, enabling accurate handling of values exceeding the i64 range and accommodating mixed data types. Addressed i64 overflow issues in the IO path, ensuring robust schema detection for large datasets and improving data ingestion reliability for users with large-integer data. Developed and integrated comprehensive unit tests to validate schema inference for both large integers and mixed data scenarios, reducing the risk of future regressions. Leveraged expertise in Rust and Python programming, data processing, and unit testing to deliver performance-conscious changes aligned with repository standards and customer needs.