DYNAMIC PARTITIONING OF SIGNATURE FILES

The signature file access method has proved to be a convenient indexing technique, in particular for text data. Because it can deal with unformatted data, many application domains have shown interest in signature file techniques, e.g., office information systems, statistical and logic databases. We argue that multimedia databases should also take advantage of this method, provided convenient storage structures for organizing signature files are available. Our main concern here is the dynamic organization of signatures based on a partitioning paradigm called Quick Filter. A signature file is partitioned by a hashing function and the partitions are organized by linear hashing. Thorough performance evaluation of the new scheme is provided, and it is compared with single-level and multilevel storage structures. Results show that quick filter is economical in space and very convenient for applications dealing with large files of dynamic data, and where user queries result in signatures with high weights. These characteristics are particularly interesting for multimedia databases, where integrated access to attributes, text and images must be provided.