Scalable conflict detection in transaction management

Abstract

Multi-thread systems and methods are described for concurrently handling requests to commit data updates to a database by a plurality of data transactions. The database preferably supports multi-versioning and the data transactions are preferably isolated by snapshot isolation. In one embodiment, concurrent and lock-free handling of requests to commit data updates includes performing two types of concurrent data conflict detection. A transaction proceeds to commit only if it passes both types of conflict detection. The first type of conflict detection is based on a hash map between data keys and their commit timestamps whereas the second type of conflict detection is based on a log that keeps track of the status of transactions whose requests to commit are actively being processed. In another embodiment, concurrent conflict detection for data items in concurrent transactions is broken down into buckets and locks are used for accessing each bucket. These systems and methods maintain transactional integrity to database while improving throughput by maximizing concurrency of data commits in a multi-thread environment.