Indexing for moving objects

Master'sMASTER OF SCIENC

Abstract Access Method Concurrency with Recovery

Providing high concurrency in B+-trees has been studied extensively. But few efforts have been doc-umented for combining concurrency methods with a recovery scheme that preserves well-formed trees across system crashes. We describe an approach for this that works for a class of index trees that is a generalization of the B1i’k-tree. A major feature of our method is that it works with a range of different recovery methods. It achieves this by decomposing structure changes in an index tree into a sequence of atomic actions, each one leaving the tree well-formed and each working on a separate level of the tree. All atomic actions on levels of the tree above the leaf level are independent of database transac-tions, and so are of short duration