EFFICIENT READ REPLICAS

摘要

A database system may receive a write request that specifies a modification to be made to a particular data record stored by the database system. A log record representing the modification to be made to the particular data record may be sent to a storage service of the database system. An indication (e.g., log record or other indication) that indicates a cached version of the particular data record stored in a read replica's cache is stale may be sent to a read replica. For a subsequent read of the particular data record received by the read replica, the read replica may request the particular data record from the storage service.

主权项

1. A method, comprising:
performing, by multiple nodes of a database service that includes a primary node, a plurality of read replicas each having a cache, and a distributed storage service:
receiving, from a client of the database service, a write request directed to a given data record in a database table, wherein the write request specifies a modification to be made to the given data record;generating a redo log record representing the modification to be made to the given data record;sending the redo log record to a particular server node of the distributed storage service that stores a version of the data page comprising the given data record; andsending the redo log record to the plurality of read replicas, wherein the redo log record indicates that a cached version of the given data record stored in respective caches of the plurality of read replicas is stale;wherein a subsequent request for the given data record received by a read replica of the plurality of read replicas includes the read replica requesting a current version of the given data record from the distributed storage service.