Patent ID: 7337290
Filing Date: 2008-02-26
Classification: G06F

Abstract:
1. A method for resolving a deadlock in a computing system, the computing system having a multi-node database cluster configuration in which a plurality of instances of a resource and an associated lock request queue are respectively distributed within a plurality of database nodes, the system also having a distributed lock manager comprising a collection of local lock managers, each node having a local lock manager, the method comprising: identifying a first request for an exclusive lock that is associated with the resource, the first request forming part of a deadlock in which the deadlock cannot be resolved unless the first request is granted; allowing a period of time for the first request to be granted; identifying a second request for a shared lock that exists behind the first request; and reordering a plurality of lock request queue instances to place the second request ahead of the first request in the respective lock request queue instance, the plurality of lock request queue instances comprises a lock request queue instance associated with a first database node and lock request queue instances associated with other database nodes, wherein the present configuration of locks allows the second request to be granted, and a granting of the second request initiates a chain of resource accesses that resolves the deadlock and allows the first request to be granted, in which the act of reordering comprises