Xiening Dai
Principal Engineer at The Apache Software Foundation
Seattle, Washington, United States
Summary
👤
Senior🎓
Top SchoolXiening Dai is a Principal Engineer with nine years of focused experience building and optimizing large-scale query execution, storage engines, and distributed data platforms. Currently at Amazon working on query execution and optimization, he previously led architecture and performance work on Alibaba's MaxCompute — an exabyte-scale columnar storage and vectorized execution platform. A long-time Apache contributor and committer on projects like ORC and Calcite, his open-source work includes optimizer improvements, metadata caching fixes, and core ORC streaming implementations that improve real-world query performance. He has deep systems experience from Microsoft Edge’s front-tier services to design of low-latency telemetry pipelines, and has driven both algorithmic and platform-level optimizations. Comfortable across C++, Java, and systems-level engineering, he combines hands-on implementation with technical leadership on production at internet scale. Peers value him for pragmatic optimizations that reveal measurable gains in throughput and cost at massive scale — work that often surfaces in popular Apache projects.
9 years of coding experience
14 years of employment as a software developer
Master, Computer Science and Engineering, Master, Computer Science and Engineering at South China University of Technology
Chinese
Github Skills (20)
apache-calcite10
c-language10
bit-manipulation10
query-optimization10
big-data10
java10
calc10
javas10
sql10
orc10
cpp10
cprogramming-language10
relational-algebra10
unit-testing9
zlib9
Programming languages (4)
Github contributions (5)
apache/orc
May 2017 - Mar 2019
Apache ORC - the smallest, fastest columnar storage for Hadoop workloads
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 review, 7 commits, 22 PRs in 1 year 10 months
Contributions summary:Xiening implemented core features and optimizations for the Apache ORC project, a columnar storage format. Their primary contribution focused on creating an OutputStream interface and its implementation, crucial for data writing. This involved developing the `BufferedOutputStream` and `AppendOnlyBufferedStream` classes, alongside adding unit tests for the functionality. The changes also demonstrate work on compression streams (ZLIB).
hadooporcjavabig-dataapache
apache/calcite
Aug 2019 - Apr 2020
Apache Calcite
Role in this project:Back-end Developer
Back-end DeveloperContributions:15 commits, 22 PRs, 151 comments in 7 months
Contributions summary:Xiening primarily contributed to the Apache Calcite project, focusing on improvements to the query optimization and planning aspects of the system. They addressed issues related to metadata caching, best RelNode selection within subsets, and cost propagation strategies in the VolcanoPlanner. Their work included refactoring and bug fixes to improve the consistency and performance of the query optimizer. They also worked on handling exceptions related to metadata queries.
apache-calcitegeospatialcalcitejavabig-data
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