154results about How to "Avoid contention" patented technology

Access to a shareable resource between threads is controlled by a lock having shared, optimistic and exclusive modes and maintaining a list of threads requesting ownership of said lock. A shared optimistic mode is provided. A lock state descriptor is provided for each desired change of mode comprising a current mode in which a thread has already acquired the lock. When a thread acquires the lock in shared optimistic mode, other threads are allowed to acquire the lock in shared or optimistic mode. When a thread which acquired the lock in shared optimistic mode wants to acquire the lock in exclusive mode, other threads which have acquired the lock in shared or optimistic mode are prevented from acquiring the lock in exclusive mode until the thread which acquired the lock in shared optimistic mode and requested to acquire the lock in exclusive mode releases the lock.

An object of the present invention is to avoid contention for resources in a parallel / decentralized database system so as to improve the performance of the system. A query posing method is implemented in a database system comprising a plurality of database servers each of which includes a database from which the same content can be retrieved and searches the database in response to a query request a front-end server that poses a query according to a predetermined rule and a management server that manages rules to be used by the front-end server. The management server acquires a processed query log relevant to a database server, and produces a rule according to the compatibility value of a query calculated using the acquired processed query log. Moreover, the front-end server poses the query according to the rule produced by the management server.

In an interconnection network, multiple nodes are connected to one of a first layer of switches. The first layer of switches is connected to one another through a second layer of switches, wherein each of the nodes is connected through one of multiple shared links connecting the first layer switches and the second layer of switches. A pipelined broadcast manager schedules a hierarchical pipelined broadcast through at least one switch of the first layer switches comprising a multiple non-root nodes by selecting two nodes of multiple non-root nodes connected to the at least one switch and scheduling each of multiple broadcast steps for the pipelined broadcast with at least one of an inter-switch broadcast phase and an intra-switch broadcast phase. The inter-switch broadcast phase is scheduled with a first node of the two nodes receiving a first data packet from another switch from among the first layer of switches and a second node of the two nodes sending a second data packet previously received from another switch to one other switch from among the first layer switches. The intra-switch broadcast phase is scheduled with the first node acting as a source for sending a previously received data packet to at least one other non-root node and the second node acting as a sink for receiving the previously received data packet, wherein each of the non-root nodes sends and receives the previously received data packet once throughout the broadcast steps and the sink receives the previously received data packet last. In scheduling the hierarchical pipelined broadcast, the first node and the second node alternate roles each broadcast step.

In a storage area network (SAN), different tasks may expect different types of commands for commencing execution, such as interactive or offline, and may have different formats for reporting status and completion, such as log files or message based. A framework for defining the business logic enveloped in a particular task, and providing a common manner of deploying, or enabling invocation, of the task provides consistent operator control for scheduling, monitoring, ensuring completion, and tracking errors and other events. Business logic modules are identified as commands corresponding to a task. Transactions including a set of the commands define an ordered sequence for completing the task. The operator requests a particular set of tasks, using a selection tree, and the task manager builds a corresponding execution tree to identify and map the transactions and commands of the task to the execution tree to optimize execution and mitigate redundancies.

A memory circuit has a plurality of blocks which further comprises a plurality of regular sectors and a spare sector, wherein each sector further comprises a plurality of memory cells, and when a regular sector in a first block is defective, this defective regular sector is replaced with a spare sector in a second block. And responding to an address to be supplied, the regular sector corresponding to the supplied address in the first block and the spare selector in the second block are selected simultaneously during a first period, and after the first period, selection of one of the regular sector and the spare sector is maintained according to the result of redundancy judgment on whether the supply address matches with the redundant address. Regardless the result of redundancy judgment on whether the supplied address matches the redundant address indicating the defective sector, a regular sector in the first block and the spare sector in the second block, to be a pair thereof, are set to selected status simultaneously during the first period when access operation stars, so a drop in access speed due to a redundancy judgment operation can be suppressed.