QeDB: A Quality-Aware Embedded Real-Time Database

QeDB is a database for data-intensive real-time applications running on flash memory-based embedded systems.Currently, databases for embedded systems are best effort,providing no guarantees on its timeliness and data freshness. Moreover, the existing real-time database (RTDB) technology can not be applied to these embedded databases since they hypothesize that the main memory of a system is large enough to hold all database, which can not be true in data-intensive real-time applications. QeDB uses a novel feedback control scheme to support QoS in such embedded systems without requiring all data to reside in main memory.In particular, our approach is based on simultaneous control of both I/O and CPU resource to guarantee the desired timeliness. Unlike existing work on feedback control of RTDB performance, we actually implement and evaluate the proposed scheme in a modern embedded system.The experimental results show that our approach supports the desired timeliness of transactions while still maintaining high data freshness compared to baseline approaches.