Abstract

We examine issues in the design of fully dynamic information retrieval systems with support for instantaneous document insertions and deletions. We present one such system and discuss some of the major design decisions. These decisions affect both the indexing and the query processing efficiency of our system and thus represent genuine trade-offs between indexing and query processing performance. Two aspects of the retrieval system – fast, incremental updates and garbage collection for delayed document deletions – are discussed in detail, with a focus on the respective trade-offs. Depending on the relative number of queries and update operations, different strategies lead to optimal overall performance. Special attention is given to a particular case of dynamic search systems – desktop and file system search. As one of the main results of this paper, we demonstrate how security mechanisms necessary for multiuser support can be extended to realize efficient document deletions.

Citations