Embodiments allow a primary database system (“primary”) to automatically detect queries directed to the primary database that may be offloaded to a standby database system (“standby”), and then to automatically offload the offload-eligible queries to a standby. The primary identifies offload-eligible queries based on a record of up-to-date database objects within each standby that replicates the primary database. The record of up-to-date standby objects is updated based on heartbeat messages from each standby, and commit timestamps for transactions on the primary. Evaluation of whether a query is offload-eligible is triggered by one or more trigger conditions that include: inclusion of an offload optimizer hint in the query, an estimated run-time of the query, etc. Embodiments further allow an offloaded query over particular changed data in the primary database to access, on a standby database, uncommitted changes made to the particular data in the primary database.