Worked on the databendlabs/databend repository to address a critical issue in the query planner related to constant table scans. Focused on database internals and query optimization using Rust, the developer fixed a bug where lazy columns were not preserved when filters rewrote to an empty scan. The solution involved implementing a clear_lazy_columns function and integrating it into the rule_eliminate_filter.rs module. To ensure ongoing reliability, a dedicated regression test was added to validate the fix and prevent future regressions. This work improved the correctness of query results and strengthened regression coverage, contributing to the project’s overall stability.