The StarBase Project Overview
StarBase Overview
- built on top of the RT-Mach operating system
- supports real-time transactions with firm deadlines
- seeks to minimize the number of high-priority transactions which miss their deadlines
- uses no a priori information about the transaction workload
Problems Faced by Real-Time Databases
- resource contention
- data contention
- specifying/enforcing timing constraints
Dealing with Resource Contention
- RT-Mach provides:
- priority-cognizant thread scheduling and a real-time thread model
- Basic Priority Inheritance synchronization for non-preemptible resources
- StarBase employs these features to:
- service transactions in priority order
- ensure transactions progress according to priority
- ensure transactions access resource managers in priority order
Dealing with Data Contention
- WAIT-X(S) optimistic concurrency control
- priority-based commit test
- Precise Serialization to reduce unnecessary aborts
Enforcing Deadlines
- RT-Mach provides:
- real-time thread model
- real-time clocks and timers
- StarBase uses these features to abort transactions and reply at or before deadline
- StarBase:
- avoids race conditions between deadline handler and transaction
- avoids interference by low-priority transactions
Future Work
- incorporate a priori information/offline analysis for predictability
- port to other real-time OS kernels that support POSIX .4 extension
Other Projects:
[Starbase]
[Security]
[Predict]
[Schedule]
[Multimedia]
[Dependability]
Last modified: Mon Oct 2 18:34:05 EDT 1995 [SK]