Providing read committed isolation level in non-blocking ROWA database replication protocols

Abstract. Total order ROWA strategies are widely used in replicated protocol design. Normally, these protocols provide higher isolation guarantees like Serialisable or Snapshot Isolation but, for some applications, a more permissive isolation level like Read Committed fits better. Some centralised database management systems provide Read Committed as a default isolation level but in replicated systems it is rare to find proposals and systems supporting it. In this paper we extend the notion of Read Committed to a replicated environment, giving the necessary theoretical background to construct Read Committed ROWA database replication protocols.