Dynamic Timestamp Allocation for Reducing Transaction Aborts

CockroachDB is an open-source database, providing transactional access to data in a distributed setting. CockroachDB employs a multi-version timestamp ordering protocol to provide serializability. This provides a simple mechanism to enforce serializability, but the static timestamp allocation scheme can lead to a high number of aborts under contention. We aim to reduce the aborts for transactional workloads by integrating a dynamic timestamp ordering based concurrency control scheme in CockroachDB. Dynamic timestamp ordering scheme tries to reduce the number of aborts by allocating timestamps dynamically based on the conflicts of accessed data items. This gives a transaction higher chance to fit on a logically serializable timeline, especially in workloads with high contention.