On Wed, Jun 22, 2016 at 9:36 PM, Craig James <cjames@emolecules.com> wrote: > On Wed, Jun 22, 2016 at 11:36 AM, Jeff Janes <jeff.janes@gmail.com> wrote: ... But, JChem's cartridge is apparently not using a GiST index, which is what my first guess was. I can't really figure out what PostgreSQL API it is tapping into, so whatever it is very well might not support multi-column indexes at all.
They run a separate chemistry server process, which I believe is a Java app. My guess (and it's strictly a guess) is that they use classic chemical bitmap fingerprints, and the index scan runs in their separate process and only returns the index-scan results.
