Jung-Sang Ahn
안정상 (in Korean)
Software Engineer at eBay.
LinkedIn
Github
Interests
- Indexing, caching, replication, key-value store.
- Distributed systems, storage/file systems, operating systems.
- Problem solving, optimizing performance.
- Electric/acoustic guitar, finger-style guitar, band session,
song writing, recording/mixing/mastering.
- Snowboarding, go-kart, road cycling, high performance driving.
Employment and Education
- Member of Technical Staff, Distributed Systems,
eBay,
2017 - present.
- Senior Software Engineer,
Couchbase,
2015 - 2017.
- Ph.D. in
Computer Science
(Computer Architecture and Systems Lab),
KAIST,
2010 - 2015.
- M.S. in
Computer Science
(Computer Architecture and Systems Lab),
KAIST,
2008 - 2010.
- B.S. in
Computer Science,
KAIST,
2004 - 2008.
- Presidential scholarship, the Korean government.
- Daejeon Science High School,
2002 - 2004.
- Early graduation, 2 years.
Experience
eBay
- Lead developer of distributed database core engine
(Designed and developed in-house engines from scratch)
- Replication engine: Paxos, Raft, and variants.
- Storage engine: B+tree, LSM-tree,
append-only logs, and variants.
- Query engine: executing SQL-like expressions using low-level key-value store operations.
- Distributed transaction.
- Multi-master replication across multiple data centers, and its conflict resolution logic.
- Synchronous and unique global secondary index.
- Continuous backup and point-in-time restoration.
- Change data capture, pipelining operation and re-do logs.
- Management of the entire life cycle of products: designing, development, testing, deployment, operation, and monitoring.
Couchbase
- Key-value storage engine
- Original author of
ForestDB
- Storage engine embedded in NoSQL server & mobile platform.
- Optimizing file system and disk I/O patterns.
KAIST
- Index structures for block devices
- Designing flash-optimized index structure for FTL
(Flash Translation Layer) in SSD controller.
- Mobile/embedded device kernel
- Designing lightweight encryption file system for Android platform.
- Linux kernel optimization.
Personal Projects
Publications and Patents
-
Designing an Efficient Replicated Log Store with Consensus Protocol
[PDF]
Jung-Sang Ahn, Woon-Hak Kang, Kun Ren, Guogen Zhang,
and Sami Ben-Romdhane
USENIX HotCloud, 2019.
-
Jungle: Towards Dynamically Adjustable Key-Value Store
by Combining LSM-Tree and Copy-On-Write B+-Tree
[PDF]
Jung-Sang Ahn, Mohiuddin Abdul Qader, Woon-Hak Kang,
Hieu Nguyen, Guogen Zhang, and Sami Ben-Romdhane
USENIX HotStorage, 2019.
-
GRIT: Consistent Distributed Transactions across Polyglot
Microservices with Multiple Databases
[PDF]
Guogen Zhang, Kun Ren, Jung-Sang Ahn, and Sami Ben-Romdhane
IEEE International Conference on Data Engineering (ICDE) (Demo), 2019.
-
Session Guarantees with Raft and Hybrid Logical Clocks
Mohammad Roohitavaf, Jung-Sang Ahn, Woon-Hak Kang, Kun Ren,
Gene Zhang, Sami Ben-Romdhane, and Sandeep S. Kulkarni
International Conference on Distributed Computing and Networking (ICDCN), 2019.
-
Key-Value Replication with Consensus Protocol
Sami Ben-Romdhane, Jung-Sang Ahn, and Guogen Zhang
Patent No. 10838977 (December 26, 2019), United States.
-
ForestDB: A Fast Key-Value Storage System for Variable-Length String
Keys
Jung-Sang Ahn, Chiyoung Seo, Ravi Mayuram, Rahim Yaseen,
Jin-Soo Kim, and Seungryoul Maeng
IEEE Transactions on Computers, 2016.
-
Low-Overhead User Data Protection for Smartphones using
Plaintext Cache
Jung-Sang Ahn and Seungryoul Maeng
Mobile Security Technologies (IEEE Symposium on Security and Privacy),
2013.
-
μ*-Tree: An Ordered Index Structure for NAND Flash Memory with
Adaptive Page Layout Scheme
Jung-Sang Ahn, Dongwon Kang, Dawoon Jung, Jin-Soo Kim,
and Seungryoul Maeng
IEEE Transactions on Computers, 2013.
-
Indexing Method for Flash Memory
Jaesoo Lee, Jung-Sang Ahn, Jin-Soo Kim, and Dawoon Jung
Patent No. 8799558 (August 5, 2014), United States.
-
Indexing Method for Flash Memory
Jaesoo Lee, Jung-Sang Ahn, Jin-Soo Kim, and Dawoon Jung
Patent No. 10-1699779 (January 19, 2017), Korea.
Honors and Awards
-
Third Place, ACM SIGMOD Programming Contest, 2012.
A Multi-Dimensional Indexing System
-
Finalist, ACM SIGMOD Programming Contest, 2011.
A Durable Main-Memory Index Using Flash
-
Bronze Prize, Samsung Humantech Paper Award, 2008.
-
Silver Prize, Samsung Humantech Paper Award, 2004.
-
Honorable Mention, Samsung Humantech Paper Award, 2003.
-
Finalist, Intel ISEF (International Science and Engineering Fair), 2002.
-
Gold Medal, KOI (Korea Olympiad in Informatics), 2001.
Services
-
Journal paper referee, ACM Transactions on Storage, 2020.
-
Program committee, Scalable Cloud Data Management (IEEE Big Data), 2020.
-
Program committee, Scalable Cloud Data Management (IEEE Big Data), 2019.
-
Program committee, Scalable Cloud Data Management (IEEE Big Data), 2018.
-
Journal paper referee, ACM Transactions on Storage, 2017.
-
Journal paper referee, IEEE Transactions on Computers, 2015.
-
Journal paper referee, IEEE Transactions on VLSI Systems, 2014.
-
Journal paper referee, IEEE Transactions on Computers, 2013.
-
Journal paper referee, IEEE Transactions on Computers, 2012.
Contact Information