Method for non-hierarchical lock management in a multi-system shared data environment

摘要

In a combination of multiple concurrently-executing database management systems which share data storage resources, efficient lock processing for shared data is implemented by hiding from a global lock manager the distinction between transaction-interest and cache-interest locks that are processed at the DBMS level. The local lock manager of a DBMS, in response to a request for either type of lock, may issue a request to the global lock manager for a system-level lock without disclosing to the global lock manager the type of lock requested of the local lock manager. After receipt of the system level lock, the local lock manager can grant either transaction or cache interest locks locally on a data resource if the combined mode of locally-held locks on that data resource is greater than or equal to the requested mode.