Hello Mark, On Sun, 2011-01-16 at 14:21 +1100, Mark James wrote:
> Is there an easy way to determine the amount of disk space an > individual quad store graph is taking up? Indexes for IRIs and literals are common for all graphs, so it's not obvious how to count the consumed space if an IRI is used in more than one graph. Accounting for quads becomes unclear too. Before version 6 it was possible at least to get the size of indexes for quads, divide it by total number of quads in all graphs (to get a disk cost of a single quad) and multiply by number of quads in the specified graph, thus some adequate number was available. Starting from version 6, there are partial indexes on S,P and O,P, as a part of "3+2" indexing model, and data of these indexes are shared for all graphs, so not counting is possible for same reason as for IRIs. In addition, indexes become bitmaps with compression that can sometimes save significant amounts of additional data "for free". So I don't know what to recommend as a reasonable measurement method. Existing real-life storages may give some hint, but not more, experiments with synthetic data like benchmarks does not give even a hint, because they're "too synthetic". Best Regards, Ivan Mikhailov OpenLink Software http://virtuoso.openlinksw.com
