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.

Abstract: A cross-region data distribution service enables eventually consistent replication of data objects between geographical regions while maintaining data ordering guarantees. For data replication between two regions, the system leverages a data stream-based replication model where destination region leverages a watch API exposed by origin regions. The origin region watch API provides a resumable data stream for changes happening in the origin region that need to be replicated to destination. The system exposes distribution ability through distribution policies which are global objects that encode the source datasets and desired distribution topology. In order to solve data fanout scalability challenges where same data needs to be replicated to many regions, system leverages caching at origin watch servers. The system maintains data ordering by enforcing ordered replication stream provided by watch servers and using version based conditional optimistic concurrency control writes in destination servers.

Abstract: According to various embodiments, techniques and mechanisms described herein facilitate the identification of fraudulent request messages. In one example, a request message associated with a user identifier is received at a request server in a request system that includes a plurality of such request servers. An estimated message count value associated with the user identifier is identified. The estimated message count value identifies an estimated number of messages associated with the user identifier that were previously received by the request servers. A response message is transmitted when it is determined that the estimated message count is below a designated threshold.