PhD thesis

Thesis

1. Ph.D.

   The Evolution of Cloud Data Architectures: Storage, Compute, and Migration. Gang Liao (2022). University of Maryland, College Park.

   PDF Talk

conference papers

2022

1. TBD

   FileScale: Fast and Elastic Metadata Management for Distributed File Systems

   Gang Liao, and Daniel J. Abadi

   In Proceedings of XXXX, 2022

   Abs Code

   This paper describes FILESCALE, a three-tier architecturethat incorporates a distributed database system as part of a comprehensive approach to metadata management in distributed file systems. In contrast to previous approaches, the architecture described in the paper performs comparably to the single-machine architecture at a small scale, while enabling linear scalability as the file system metadata increases.

2. TBD

   Flock: A Practical Serverless Streaming Query Engine

   Gang Liao, Amol Deshpande, and Daniel J. Abadi

   In Proceedings of XXXX, 2022

   Code

2021

1. SIGMOD

   BullFrog: Online Schema Evolution via Lazy Evaluation

   Souvik Bhattacherjee*, Gang Liao*, Michael Hicks, and Daniel J. Abadi

   In Proceedings of SIGMOD, 2021

   Abs PDF Blog Code Slides

   This paper presents BullFrog, a relational DBMS that supports single-step, non-backwards compatible schema migrations without downtime, and without advanced warning. When a schema migration is presented, BullFrog initiates a logical switch to the new schema, but physically migrates affected data lazily, as it is demanded by incoming transactions. BullFrog’s internal concurrency control algorithms and data structures enable concurrent processing of schema migration operations with post-migration transactions, while ensuring exactly-once migration of all old data into the physical layout required by the new schema. BullFrog is implemented as an open source extension to PostgreSQL. Experiments using this prototype over a TPC-C based workload (supplemented to include schema migrations) show that BullFrog can achieve zero-downtime migration to non-trivial new schemas with near-invisible impact on transaction throughput and latency.