QuaSAQ: An Approach to Enabling End-to-End QoS for Multimedia Databases

The paper discusses the design and prototype implementation of a QoS-aware multimedia database system. Recent research in multimedia databases has devoted little attention to the aspect of the integration of QoS support at the user level. Our proposed architecture to enable end-to-end QoS control, the QoS-Aware Query Processor (QuaSAQ), satisfies user specified quality requirements. The users need not be aware of detailed low-level QoS parameters, but rather specifies high-level, qualitative attributes. In addition to an overview of key research issues in the design of QoS-aware databases, this paper presents our proposed solutions, and system implementation details. An important issue relates to the enumeration and evaluation of alternative plans for servicing QoS-enhanced queries. This step follows the conventional query execution which results in the identification of objects of interest to the user. We propose a novel cost model for media delivery that explicitly takes the resource utilization of the plan and the current system contention level into account. Experiments run on the QuaSAQ prototype show significantly improved QoS and system throughput.