PBASE/2对全局系统资源信息的管理和利用

作为基于ＳＮ体系结构的并行数据库，ＰＢＡＳＥ／２的关键问题在于如何保持系统的负载平衡，而准确、实时的系统资源信息则成为负载平衡的基础。ＰＢＡＳＥ／２的系统资源信息管理采用分布式体系结构，以系统资源利用表为基础，采用多副本、中断式部分主本封锁策略来组织和管理系统资源信息。同时基于系统资源信息，ＰＢＡＳＥ／２提出了一整套从优化到调度、完整的系统负载平衡方案。

THE MANAGEMENT AND UTILIZATION OF GLOBAL SYSTEM RESOURCE INFORMATION IN PBASE/2

As a shared nothing parallel database,one of the key problems of PBASE/2 is to keep the system load balance. And how to keep the system resource information accurate and real time become the core of this key problem. In PBASE/2, a subsystem GSRIMS(global system resource information manage system) is developed to keep the system resource information accurate and on time. According to the shared nothing structure, the authors take a distributed strategy to manage the global resource untilization information.There is one GSRIMS on each processing node, and each GSRIMS matains two tables that record the global resource utilization information.These two tables are the base data structure of GSRIMS,and they are predictive: any changes of resource utilization that have been made(and will be made) by local optimization subsystem and schedule subsystem are to be recorded. And it is the the local GSRIMS's responsibility to broadcast the local resource untilization information when the change is big enough. Consequently each GSRIMS has to refresh its global resource untilization information according to other GSRIMS's message occasionaly.Based on the global resource untilization information that GSRIMS provide, PBASE/2 gives a total solution to keep the system load balance,such as 3 Phase Optimization,dynamic scheduling and so on.