> As others pointed out semantically the evaluation of the two query forms > yields very different intermediate results. It's only the presence of the > post-processing CONSTRUCT stage that happens to strip out the > duplicates/unusable results. Any optimizations MUST preserve the overall > semantics of the query to ensure they yield the same results, so no you > couldn't apply an optimization in this case. In this specific case CONSTRUCT > happens as a post-processing step as part of producing the final query > results, it's not actually within the portion of query evaluation that is > subject to ARQs optimizer.
Thanks! I still don't understand though... is there a reason why the ARQs optimizer can't have a boolean flag telling it it can optimize things for a CONSTRUCT? Best, -- Elie
