Real-Time Data You Can Trust: Deterministic and Reliable
Why it matters
In real-time systems, every database transaction must complete within its deadline—committing if it makes the cutoff, or aborting if it doesn’t. Missing a transaction deadline—whether by commit or rollback—can never be allowed, because it risks corrupting the system. eXtremeDB/rt enforces firm transaction deadlines, ensuring data consistency and fully deterministic behavior.
How eXtremeDB/rt handles deadlines
eXtremeDB/rt allows applications to hand transaction deadlines and priorities directly to the database kernel, which applies the High-Priority Earliest-Deadline-First (EDF) or Priority Inheritance (PI) scheduling algorithms. Update transactions run sequentially, while read-only transactions can run in parallel.
The database kernel continuously compares elapsed time against the transaction deadline at frequent control points. If a transaction risks overrunning, it is flagged as interrupted, execution is stopped, and control is returned to the application. The kernel then rolls back any changes, restoring the database to its previous consistent state. Rollback is always bounded and takes less time than the work already performed, keeping transaction timing predictable.
This design ensures that even when a transaction misses its deadline, it does so in a controlled way and never runs past the allotted time. The result is a database kernel that preserves consistency and deterministic behavior under real-time constraints. A more comprehensive description of these mechanisms is available in the product documentation and supporting technical materials.
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Beyond real-time
Deterministic transaction scheduling is supported for in-memory databases and for systems that store data directly on unmanaged flash media through the database kernel’s Transactional Flash Translation Layer (TFTL™) module.
These unique capabilities, unavailable in conventional databases, make it possible to enforce transaction deadlines even in persistent storage environments. At the same time, eXtremeDB/rt also supports conventional, non-real-time transactions when strict timing guarantees are not required. The result is a single database platform that adapts seamlessly to both real-time and non-real-time applications.
To support deployment, monitoring, and management of these systems, eXtremeDB/rt includes the EWSLite connectivity framework and RESTrt monitoring services. Together they expose database, storage, and transaction statistics through standard REST APIs and web-based interfaces. Available metrics include memory utilization, I/O activity, storage performance, transaction activity, and real-time deadline compliance statistics, including transactions that met or missed their execution deadlines.