Database system with methods for parallel lock management
US5832484A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1996 |
| Grant date | Nov 3, 1998 |
| Priority date | — |
| Expiry date | Jul 2, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99939
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Database system and methods are described for improving scalability of multi-user database systems by improving management of locks used in the system. The system provides multiple server engines, with each engine having a Parallel Lock Manager. More particularly, the Lock Manager decomposes the single spin lock traditionally employed to protect shared, global Lock Manager structures into multiple spin locks, each protecting individual hash buckets or groups of hash buckets which index into particular members of those structures. In this manner, contention for shared, global Lock Manager data structures is reduced, thereby improving the system's scalability. Further, improved "deadlock" searching methodology is provided. Specifically, the system provides a "deferred" mode of deadlock detection. Here, a task simply goes to sleep on a lock; it does not initiate a deadlock search. At a later point in time, the task is awakened to carry out the deadlock search. Often, however, a task can be awakened with the requested lock being granted. In this manner, the "deferred" mode of deadlock detection allows the system to avoid deadlock detection for locks which are soon granted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.