Concurrency and recovery for index trees with nodal updates using multiple atomic actions by which the trees integrity is preserved during undesired system interruptions

摘要

The present invention includes an approach to index tree structure changes which provides high concurrency while being usable with many recovery schemes and with many varieties of index trees. The present invention permits multiple concurrent structure changes. In addition, all update activity and structure change activity above the data level executes in short independent atomic actions which do not impede normal database activity. Only data node splitting executes in the context of a database transaction. This feature makes the approach usable with diverse recovery mechanisms, while only impacting concurrency in a modest way. Even this impact can be avoided by re-packaging the atomic actions, at the cost of requiring more from the recovery system.