• • Owned PL(Procedural Language) Compiler module, which worked as a [PLSQL](https://docs.oracle.com/en/database/oracle/oracle-database/21/lnpls/index.html) plugin to Transwarp's distributed database product _[KunDB](https://www.transwarp.cn/en/product/kundb)_. Shipped a production version in only __6 months__ and added huge value to the product, which helped customers with Oracle infrastructure __migrate smoothly__ to Transwarp KunDB.
• • Developed the expression eval engine with vectorization and cache locality technology. Achieved over __100% performance boost__ compared to non vectorized engine and became a selling point of KunDB.
• • Decoupled PL engine code from SQL engine. Improved __modular design and code maintainability__.
• • Enabled PL engine exchange __streaming__ data with SQL engine, over __50% faster__ than non-streaming way.
• • Improved __Oracle compatibility__: Led PL name resolution and Oracle type system development in SQL compiler; Innovated a solution that extended YACC grammar from context free to context sensitive to resolve syntax ambiguity and support more Oracle syntax with no pain.