Sang K. Cha

Visiting from Seoul National University


While visting the database research group of Stanford University during the 2001-2002 academic year, Sang Cha organized the weekly Stanford CS545 database seminar for the Fall quarter( and the Spring quarter(

He received his Ph.D. in the database area from Stanford in 1991 (with Gio Wiederhold as advisor) and has been on the faculty of Seoul National University of Korea since 1992. Before going back to Korea, he had working experience at Texas Instruments, Inc., IBM Palo Alto Scientific Center, and HP Laboratories. His exposure to of the personal in-memory object manager system project at HP Labs. motivated Sang Cha to work on multiple, full-blown versions of memory-centric database engines with recovery and concurrency control for the past ten years. The last one called P*TIME incorporates the recent innovative ideas of Sang Cha's team. Local contact phone number: 1-650-743-5911

Current Project: Transact In Memory Project

The goal of the Transact In Memory project is to develop a new generation of ultra-high-performance, memory-centric database transaction processing engine for mission-critical applications. More than twenty of his current and former Ph.D. and master students are involved in the development of P*TIME, including those working for the Transact In Memory, Inc. ( that Sang Cha founded to fund the Transact In Memory project with the vision of delivering two-orders higher performance, especially, in update, than existing disk-based DBMS technologies.


P*TIME, a highly Parallel, scalable Transact In Memory Engine developed by the Transact In Memory project team, employs its own unique, patent-pending technologies such as the fully parallelized logging and recovery scheme and the cache-conscious index concurrency control scheme. As a result, it provides unprecedented multiprocessor scalability for not only read-oriented workloads but also update-intensive ones. P*TIME supports the industry standard database programming interfaces, SQL and ODBC/JDBC. In addition to multi-tier application server architecture, P*TIME supports embedding the application logic inside the database server to take full advantage of P*TIME performance in building the dedicated application servers. The same standard programming interface is provided for the embedded application server programming.

P*TIME has real-world customers. Samsung Securities, Inc., one of the largest on-line securities trading companies with 40,000 - 60,000 concurrent users, uses P*TIME in the mobile trading service under development to be launched in November, 2002. Samsung Elecronics, the world number 1 DRAM manufacturer, purchased P*TIME to handle real-time storage, archiving, and querying of the sensor data stream of 25,000 records per second with a high-level SQL DBMS. No existing DBMS technology can meet the scalability requirements of Samsung Securities, Inc. and the update processing requirements of Samsung Electronics cost-effectively.

Related Recent Talks:

Time for Change: Why Not Transact In Memory?, at ACM SIGMOD Japan symposium in Tokyo, Japan (July 6, 2001), Web Age Information Management Conference in Xian, China (, July 11, 2001), Stanford CS545 Database Seminar (, November 2, 2001)

Recent Professional Service:

PC Member, IEEE ICDE 2003

PC Co-chair, DASFAA 2003 Conference (, Kyoto, Japan (with Prof. Masatoshi Yoshikawa at NAIST; General Chair: Prof. Katsumi Tanaka, Honory Chair: Prof. Yahiko Kambayashi at Kyoto University)