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Pessimistic Concurrency-Control and Versioning to Support Database Pointers in Real-Time Databases



Dag Nyström, Mikael Sjödin, Aleksandra Tesanovic , Christer Norström, Jörgen Hansson

Publication Type:

Conference/Workshop Paper


The 16th Euromicro Conference on Real-Time Systems


IEEE Computer Society


A method that allows co-existence of soft real-time, relational database transactions and hard real-time database-pointer transactions in real-time database management systems is presented. We propose a concurrency-control algorithm that uses traditional pessimistic concurrency-control (i.e., locking) for soft transactions, and uses versioning to allow hard transactions to execute regardless of any database lock. We provide formal proof that the algorithm is deadlock free and formally verify that transactions have atomic semantics. We also present an evaluation that demonstrates significant benefits for both soft and hard transactions when our algorithm is used. The proposed algorithm is suited for resource constrained, safety critical, real-time systems that have a mix of hard real-time control applications and soft real-time management, maintenance or user-interface applications.


author = {Dag Nystr{\"o}m and Mikael Sj{\"o}din and Aleksandra Tesanovic and Christer Norstr{\"o}m and J{\"o}rgen Hansson},
title = {Pessimistic Concurrency-Control and Versioning to Support Database Pointers in Real-Time Databases},
pages = {261--270},
month = {June},
year = {2004},
booktitle = {The 16th Euromicro Conference on Real-Time Systems},
publisher = {IEEE Computer Society},
url = {}