Abstract: A method and system are provided for performing anticipatory changes to a resource governed by a locking mechanism. Entities (such as transactions in a database system) that want to modify a resource request permission to modify the resource. However, prior to receiving permission, they make anticipatory changes to a private version of the resource. The entities are prevented from making the anticipatory changes permanent until they receive permission to make the changes. Because they can make the changes, and proceed to other operations, before receiving permission, any delay in receiving permission has less adverse effect on their performance.

Abstract: In a multi-node database system, a list of data blocks to perform recovery operations on in the event of failure of a given node is dynamically maintained on another node. List is available when the given node fails, and allows the database to be made available more quickly.

Abstract: The state of locks maintained in volatile memory by the master for the resources are preserved after termination of the master. The locks are preserved by storing persistent copies of the locks. The persistently stored copies of the locks are accessible to other nodes in a multi-node system of the master. Locks for which persistent copies are stored in this way are referred to as persistent locks. A persistent copy of data is a copy that is stored in a form of memory that is able to store the copy after the volatile memory storing the data is unable to do so.

Abstract: A mechanism is described for managing the caches on nodes in a cluster. The caches are globally managed so that a data item may be retained in any cache on the nodes. This may be accomplished by, for example, a replacement policy for replacing data items stored in the buffers of the caches, where a buffer is selected for replacement in a manner that accounts for factors that include the state of the caches of other nodes. Some cached data items are designated as globally shared, and assigned (either statically or dynamically) a primary cache. For example, if a buffer holds a copy of a data item whose primary cache is another node, then the data item in the buffer is favored for replacement over a local data item or a global data item for which this is the primary cache. According to another aspect of the invention, the cache retention value of buffers on different nodes are compared, and the buffer with the lowest cache retention value is selected for replacement.

Abstract: A method and apparatus are provided for managing resources in a system that has multiple nodes. Each resource of a plurality of resources is assigned to a lock club of a plurality of lock clubs. A master node is assigned to each lock club of the plurality of lock clubs. All resources that belong to each given lock club are mastered at the master node assigned to the given lock club. Club-to-master mapping information that indicates the master node for each lock club of the plurality of lock clubs is maintained. Which of the multiple nodes is a master node for a particular resource is determined by inspecting the club-to-master mapping to determine the master node assigned to the lock club to which the particular resource belongs. The system may use directory nodes by storing the club-to-master mapping information for each lock club on a directory node that is selected for the lock club by applying a hash function to the name of the lock club.

Abstract: Methods and systems are provided for providing locking in a system. The resource objects of the system can be persistent, and thus provide finer granularity locking by allowing shared resource objects to be dynamically allocated and de-allocated. The persistent nature of the resource objects allows for the dynamic allocation and de-allocation of the resource objects, while guarding against the abnormal release of resource locks that result in the possibility of inconsistent data. If abnormal release occurs, the affected resource object(s) are marked to indicate that they are in a "dubious" state. The dubious resource objects are not dynamically de-allocated, but are instead allowed to persist until corrective or validation actions are taken. If the locks are validly released, then the resource objects can be safely de-allocated.