A DBMS for Mobile Transactions Using Bi-State-Termination

Abstract

Whenever distributed transaction processing in MANETs or other unreliable networks has to guarantee atomicity and isolation, a major challenge is how long-term blocking of resources can be avoided in case the mobile device looses connection to other participants of the transaction. We present a new technique for treating blocked data of transaction participants that wait for a coordinator's commit decision. Our technique, Bi-State-Termination (BST), gives participants that have moved during transaction execution the possibility to continue transaction processing before they know the coordinator's decision on transaction commit. The key idea of our technique is to consider both possible outcomes (commit and abort) of unknown transaction decisions. Within this paper, we describe a fast implementation of the fundamental relational database operations for a DBMS supporting the BST transaction synchronization protocol that avoids longterm transaction blocking.