The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 03, 1998
Filed:
Jul. 02, 1996
Mohan Sankaran, Alameda, CA (US);
Vaikom Bala Krishnan, Fremont, CA (US);
Sybase, Inc., Emeryville, CA (US);
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.