Abstract: System and methods for managing versions of partition maps in a distributed data store are disclosed. A relational database may use partition maps to indicate the location of data in a particular partition, or in a replica thereof. These partition maps may be versioned using a two-stage mechanism in which partition map updates are communicated to all nodes, or to affected nodes only, and in which operation may continue without waiting for acknowledgment of their application to each node. The system may handle minor partition changes differently than major partition changes. For example, if a replica of a partition is promoted to be a primary copy due to hardware or network failures, partition map changes may only be propagated to nodes in the same replica group. For major partition changes (e.g., splits, moves, mergers, added partitions, or size change), a new partition map may be made available to all nodes.

Abstract: Systems and methods for providing resource isolation in a shared computing environment using reinforcement learning (RL) techniques are disclosed. A resource isolation mechanism may be applied in a shared storage system, or database service, that limits the resource utilization of each namespace to its specified allocation. For example, the resource isolation mechanism may be used to limit the I/O utilization of database applications in a shared computing system (e.g., a system supporting a database service) to a specified limit. In such embodiments, RL techniques may be applied to the system to automatically control the rate of queries made by an application. RL techniques, such as those based on the State-Action-Reward-State-Action (SARSA) method may be effective in controlling the I/O utilization of database applications for different workloads. RL techniques may be applied globally by the service, or may be applied to particular subscribers, applications, shared resources, namespaces, or query types.

Abstract: System and methods for managing versions of partition maps in a distributed data store are disclosed. A relational database may use partition maps to indicate the location of data in a particular partition, or in a replica thereof. These partition maps may be versioned using a two-stage mechanism in which partition map updates are communicated to all nodes, or to affected nodes only, and in which operation may continue without waiting for acknowledgment of their application to each node. The system may handle minor partition changes differently than major partition changes. For example, if a replica of a partition is promoted to be a primary copy due to hardware or network failures, partition map changes may only be propagated to nodes in the same replica group. For major partition changes (e.g., splits, moves, mergers, added partitions, or size change), a new partition map may be made available to all nodes.

Abstract: System and methods for providing a Scalable Relational Database Service (SRDBS) are disclosed. SRDBS may allow a subscriber to lease/rent a virtual relational database (a.k.a. namespace) with a specified allocation of disk space, CPU resources and/or I/O resources. The namespace may resemble a physical RDBMS, and may allow client applications to perform SQL queries. SRDBS may partition a subscriber's database across multiple database servers automatically and may replicate each partition automatically. SRDBS may provide automatic routing of client queries to the appropriate database server holding the required data. The routing process may mask temporary data outages due to database replica failures, network failures, and/or repartitioning operations. SRDBS may employ partition maps to convey the location of data to client-side routing functions. These partition maps may use a multi-versioning scheme.