[Colloq] PhD Thesis Defense - Xiaowei Sun, Monday, April 4

[Rachel Kalweit]

PhD Thesis Defense
Xiaowei Sun

Thesis Title:

Online Reorganization in Parallel Database Systems: Scalability, Load
Balancing and High Availability

Time and place: Monday, April 4, 2:00pm, 366 WVH

Advisor: Betty Salzberg

Abstract:

In a highly dynamic environment, database systems need reorganization to
achieve better performance. Reorganization must be performed online in
order to provide continuous availability, and must be efficient in order
to minimize the impact on user transaction performance. In this talk I
will present my thesis work about online scaling in parallel database
systems.

The first part of the talk concerns hash-based data partitioning
strategies that distribute data evenly and rebalance efficiently when 
the system scales. In particular, I will talk about the following 
algorithms that we evaluated: (1) A linear hashing based algorithm 
Linear Hashing with Partitioning and Shifting (LHPS); (2) A hashing 
method based on prime numbers Prime Based Hashing (PBH); and (3) An 
adaptation of consistent hashing. The second part of the talk concerns 
online migration of database records and maintenance of indexes. We 
argue that database records need to be moved in batch. However, indexes 
can be updated incrementally and lazily after data migration, to 
simplify index operations, save I/O, and provide high availability. I 
will talk about the five-stage data migration algorithm and the lazy 
index maintenance algorithm.