Multiversion Altruistic Locking

TL;DR

This paper introduces a multiversion variant of altruistic locking (MAL) that relaxes constraints of previous protocols, enabling more valid schedules and enhancing concurrency in transaction management.

Contribution

It proposes a novel multiversion altruistic locking protocol that overcomes limitations of AL, and compares it with other concurrency control protocols like MV2PL and 2PL.

Findings

MAL allows more valid schedules than AL.

Comparison shows MAL's relation to other protocols in the Venn diagram.

Discussion on MAL's potential in hybrid protocols.

Abstract

This paper builds on altruistic locking which is an extension of 2PL. It allows more relaxed rules as compared to 2PL. But altruistic locking too enforces some rules which disallow some valid schedules (present in VSR and CSR) to be passed by AL. This paper proposes a multiversion variant of AL which solves this problem. The report also discusses the relationship or comparison between different protocols such as MAL and MV2PL, MAL and AL, MAL and 2PL and so on. This paper also discusses the caveats involved in MAL and where it lies in the Venn diagram of multiversion serializable schedule protocols. Finally, the possible use of MAL in hybrid protocols and the parameters involved in making MAL successful are discussed.