Compiler, IR, Optimization

• • 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.

• • Led multiple __Cloud/BI__ key projects's frontend dev including first cloud platform: _[TDC(Transwarp Data Cloud)](https://www.transwarp.cn/en/product/tdc)_.

• • Played key roles in greenfield projects, such as semantics SQL Editor. Integrated a production version of SQL Editor into _[SQLBook](https://www.transwarp.cn/en/subproduct/sqlbook)_ within __4 months__ with selling point of "intelligent hinting" on official website. Improved usability of SQL Editing and make _[SQLBook](https://www.transwarp.cn/en/subproduct/sqlbook)_ outstanding in industry.

• • Adapted new Angular+Typescript framework, which provided type safety and reduced bugs. Led the team build the __first UI Component__ library, achieved a milestone and promoted __unified UI__ across projects.

• • Improved __workflow__: Built Gitlab CI docker pipelines and set up Transwarp's private npm registry.

• • Enforced Unit Test high cover rate in frontend projects and triggered in every merge request's CI pipeline. Improved __code stability__ and reduced the number of production issues.