Efficient (In-)Consistency Management for Heterogeneous Repositories

When a group of authors collaboratively edits interrelated documents, consistency problems occur almost immediately. Current document management systems (DMS) often lack adequate facilities for consistency management. We extend traditional DMS by explicit formal consistency rules. In contrast to many other approaches, we permit inconsistencies and present the consequences to the user, which is vital for flexible document management and information management. Based on a novel semantics our tools pinpoint inconsistent document parts and tell precisely when, where, and why a repository is inconsistent. In this paper we focus on a key issue: efficient techniques for consistency rule evaluation. Our strategy is known from databases: (1) static analysis characterizes and simplifies consistency rules and (2) at run-time rules are evaluated incrementally. The major differences to databases are that we consider informal documents and explicitly allow inconsistencies. Consequently, we lack formal update descriptions and cannot rely on consistency prior to updates. The contribution of this paper is to incrementally evaluate consistency rules in the presence of previous inconsistencies. We have implemented our techniques in a revision control system. Our experiments show that efficient incremental evaluation is the key to make our approach viable.