Issues in Building Practical Provenance Systems.

The importance of maintaining provenance has been widely recognized, particularly with respect to highly-manipulated data. However, there are few deployed databases that provide provenance information with their data. We have constructed a database of protein interactions (MiMI), which is heavily used by biomedical scientists, by manipulating and integrating data from several popular biological sources. The provenance stored provides key information for assisting researchers in understanding and trusting the data. In this paper, we describe several desiderata for a practical provenance system, based on our experience from this system. We discuss the challenges that these requirements present, and outline solutions to several of these challenges that we have implemented. Our list of a dozen or so desiderata includes: efficiently capturing provenance from external applications; managing provenance size; and presenting provenance in a usable way. For example, data is often manipulated via provenanceunaware processes, but the associated provenance must still be tracked and stored. Additionally, provenance information can grow to outrageous proportions if it is either very rich or fine-grained, or both. Finally, when users view provenance data, they can usually understand a SELECT manipulation, but “why did the bcgCoalesce [1] manipulation output that?”