Oracle International Corporation

Dungara Ram Choudhary

Wilson Wai Shun Chan

Yu Kin Ho

Prasad V Bagal

Tak Fung Wang

Harish Nandyala

Richard L Long

Rajiv Wickremesinghe

Shie-rei Huang

Chandrajith Ramachandran Unnithan

Walter Battistella

Norman Lee

Techniques are provided for determining access affinity between services in a database cluster, and for placing workload of those services based, at least in part, on the access affinity. The techniques involve generating access records that indicate when sessions that are associated with each service operate on data blocks that were accessed by another session that is associated with another service. Access affinity information is generated based on the access records, where the access affinity information indicates access affinity (e.g. conflict scores) between each pair of services. The cluster then selects which node is to perform the work of a given session based on the access affinity information and the service associated with the session.

Methods and systems for conflict detection and mitigation between services in an autonomous database cloud environment

A method and apparatus are described for assigning mastership of nodes to data blocks. A method involves connecting each session of a plurality of sessions to a particular node of a cluster of nodes based on services associated with the plurality of sessions. Each session of the plurality of sessions is associated with a respective service of a plurality of services. The method also involves collecting service-based access statistics aggregated by service and ranges of data block addresses. Each range corresponds to one or more contiguous subrange of data block addresses. The method further involves assigning mastership of the nodes to the data blocks having addresses within said ranges of data block addresses based on services associated with the nodes and the service-based access statistics.

Method and systems for master establishment using service-based statistics

Techniques related to cache recovery for failed database instances are disclosed. A first database instance and a second database instance share a primary persistent storage and a secondary persistent storage. Each database instance stores, in volatile memory, a respective primary cache of a respective set of data stored on the primary persistent storage. Each database instance also stores, in volatile memory, a respective set of header data. Further, each database instance moves the respective set of data from the respective primary cache to a respective secondary cache on the secondary persistent storage. Still further, each database instance stores, on the secondary persistent storage, a respective set of persistent metadata. When the first database instance becomes inoperative, the second database instance retrieves, from the secondary persistent storage, persistent metadata corresponding to data stored in a secondary cache of the first database instance. Header data is generated based on the persistent metadata.

Cache recovery for failed database instances

A method, system, and computer program for high-availability database systems. The method commences by replicating (e.g., from a first server to a second server) a data structure having entries describing resource locks and client states. The replication can be performed to any number of servers. Upon detecting a failure of a connection between the first server and a client to which the first server is connected, the system establishes a new connection between the second server and the client by updating the replicated data structure to describe new connection between the second server and the client and updating the entries of the replicated data structure to reflect the new connection and the then current aspects of the resource locks and client states. The client can be a database instance, and the act of replicating can be accomplished using a broadcast channel. The servers can be organized in a computing cluster.

Systems and methods to retain and reclaim resource locks and client states after server failures

Growing community of inventors

Fremont, CA, United States of America

Dungara Ram Choudhary