A Deterministic Database Replication Protocol Where Multicast Writesets Never Get Aborted

Abstract

Several approaches for the full replication of data in distributed databases [1] have been studied. One of the preferred techniques is the eager update everywhere based on the total-order multicast delivery service [2], where the most outstanding varieties are: certification-based and weak-voting [1]. Under this approach, the execution flow of a transaction can be split into two different main phases: the first one, all operations are entirely executed at the delegate replica of the transaction; and followed by the second phase, started when the transaction requests its commit, all updates are collected and grouped (denoted as writeset) at the delegate replica and sent to all replicas. The commitment or abortion of a transaction is decided upon the delivery of the message. In the case of certification-based ones, each replica holds an ordered log of already committed transactions and the writeset is certified [3], against the log, to commit or abort the transaction. On the other hand, weak-voting ones atomically apply the delivered writeset at remote replicas whilst the delegate, if it is still active, reliably multicasts [2] a commit message. Thus, the certification-based presents a better behavior in terms of performance, only one message is multicast per transaction, but with higher abortion rates [1]. Recently, due to the use of DBMS providing SI, we have found several certification-based protocols to achieve, actually a weaker form called GSI [3], this isolation level in a replicated setting [3] while quite a few weak-voting ones [4].

This work has been partially supported by the EU FEDER and Spanish MEC under grant TIN2006-14738-C02.