Patent ID: 9031923
Filing Date: 2015-05-12
Classification: G06F,H04L

Abstract:
1. A first application server, comprising a computer, and configured to interface with: a database server having shared data; a centralized control unit; and a plurality of additional application servers; said first application server comprising: a cache unit which caches at least a portion of the shared data; an access control unit coupled to said cache unit and the database server; an execution unit coupled to said access control unit, said access control unit obtaining a request to access the shared data from said execution unit; a distributed control unit; and a selection unit coupled to said access control unit, said distributed control unit, the plurality of additional application servers, and the centralized control unit, said selection unit selecting one of a distributed mode wherein a lock associated with said request is obtained from said distributed control unit, a centralized read mode wherein a lock associated with said request is obtained from the centralized control unit, and a centralized update mode wherein a lock associated with said request is obtained from the centralized control unit; wherein said distributed mode permits reading from said cache and reading from the database server but prohibits updating the database server; said centralized read mode prohibits reading from said cache and updating the database server but permits reading from the database server; and said centralized update mode prohibits reading from said cache but permits reading from and updating the database server.