Systems and methods for low latency watches

Abstract

Systems and methods provide low-latency, ordered delivery of database change events to a watch client. In response to a database (DB) create, update, or delete (CUD) request, the system writes the request to a database. The database usually provides a change data capture stream of events to a publish/subscribe (pub/sub) system. This results in higher change event delivery latency and is referred to as a slow path. The system leverages a dual write approach, where the system asynchronously writes a corresponding change event directly to a fast path pub/sub system. A watch server consumes change events from the slow and fast path pub/sub systems and merges and orders the change events using a first-in first-out cache. An ordered event stream can be transmitted to the watch client with lower latency. The ordered event stream includes one or more batches, and each batch comprises a most recent change event version for each object that was changed.