Concurrent indexes are hard to build by requiring complex, careful yet error-prone processes of design and implementation. As prior work has observed, modeling indexes as transactional tables can largely ease programming. The developer only needs to write single-threaded logic without worrying about concurrency or persistence, which are transparently supported by ACID table operations. However, this was deemed infeasible due to high overheads caused by the underlying OLTP engine. In this paper, we argue that by adapting recent OLTP techniques which have been shown to deliver unprecedented performance, this idea is now feasible. We propose Tabular, a new library for building efficient indexes by modeling indexes as ACID tables which provide concurrency and persistence transparently. We elaborate the design of Tabular and its use cases. Our evaluation shows that compared to hand-crafted ones, indexes built using Tabular provide competitive performance with improved programming efficiency.

Modern database applications often change their schemas to keep up with the changing requirements. However, support for online and transactional schema evolution remains challenging in existing database systems. Specifically, prior work often takes ad hoc approaches to schema evolution with "patches" applied to existing systems, leading to many corner cases and often incomplete functionality. Applications therefore often have to carefully schedule downtimes for schema changes, sacrificing availability. This paper presents Tesseract, a new approach to online and transactional schema evolution without the aforementioned drawbacks. We design Tesseract based on a key observation: in widely used multi-versioned database systems, schema evolution can be modeled as data modification operations that change the entire table, i.e., data-definition-as-modification (DDaM). This allows us to support schema almost "for free" by leveraging the concurrency control protocol. By simple tweaks to existing snapshot isolation protocols, on a 40-core server we show that under a variety of workloads, Tesseract is able to provide online, transactional schema evolution without service downtime, and retain high application performance when schema evolution is in progress.