Abstract: Techniques are described for preserving the inflight sessions failing over from a primary database to the replicated logical database of the primary database. In an implementation, prior to failover, when the primary database server receives a commit for a transaction, the process stores a commit indication that the transaction has been committed by performing a corresponding SQL command. The commit indication is replicated to the logical replica database by virtue of the replication of the SQL command and its execution on the logical replica database. Accordingly, the standby database server in the failover session may successfully request for the outcome of the transaction. Techniques are also described for the client-side LOB references to be preserved when failing over to the logical replica database, for AS OF queries preserved, and for versioning of checksums, signatures and structures across logical replicas.

Abstract: A system and method for communicating a side effect of a data request, from a data server and through one or more caches, inline with a response to the request. Instead of sending a separate notification of the side effect (e.g., instructions to invalidate data cached in one or more caches), the notification is included in the response. As the response traverses caches on its way to the requestor, each cache applies the side effect with the proper timing. Thus, data invalidation may be performed prior to caching data included in the request and/or forwarding the response toward the requester. A final cache configured to serve the response to the requestor may remove the side effect notification before serving the response.

Abstract: A system and method for communicating a side effect of a data request, from a data server and through one or more caches, inline with a response to the request. Instead of sending a separate notification of the side effect (e.g., instructions to invalidate data cached in one or more caches), the notification is included in the response. As the response traverses caches on its way to the requestor, each cache applies the side effect with the proper timing. Thus, data invalidation may be performed prior to caching data included in the request and/or forwarding the response toward the requester. A final cache configured to serve the response to the requestor may remove the side effect notification before serving the response.