On Fri, Nov 02, 2012 at 04:05:30PM +0400, Alexander Korotkov wrote: > On Thu, Oct 18, 2012 at 11:18 PM, Noah Misch <n...@leadboat.com> wrote:
> > > --- 1339,1356 ---- > > > *recheck = false; > > > break; > > > case BoxStrategyNumberGroup: > > > ! /* > > > ! * This code repeats logic of on_ob which uses > > simple comparison > > > ! * rather than FP* functions. > > > ! */ > > > ! query = PG_GETARG_BOX_P(1); > > > ! key = DatumGetBoxP(entry->key); > > > ! > > > ! *recheck = false; > > > ! result = key->high.x >= query->low.x && > > > ! key->low.x <= query->high.x && > > > ! key->high.y >= query->low.y && > > > ! key->low.y <= query->high.y; > > > > For leaf entries, this correctly degenerates to on_pb(). For internal > > entries, it must, but does not, implement box_overlap(). (The fuzzy > > box_overlap() would be fine.) I recommend making gist_point_consistent()'s > > treatment of boxes resemble its treatment of circles and polygons; that > > eases > > verifying their correctness. Call gist_box_consistent. Then, for leaf > > entries, call box_contain_pt(). > > > > I have two objections on doing that: > 1) It's not evident for me that fuzzy comparison in internal pages is fine. > Obviously, it depends on data distribution. It's easy to provide an example > when fuzzy comparison will lead to significant performance degradation. > 2) With PolygonStrategyNumberGroup CircleStrategyNumberGroup it's faster to > do simple box comparison than doing calculation for exact circle and > especially polygon check. In this case previous filtering in leaf pages > looks reasonable. With BoxStrategyNumberGroup exact calculation is simpler > than gist_box_consistent. That's fair; I withdraw the recommendation to use gist_box_consistent(). It remains that the code here must somehow implement a box_overlap()-style calculation for internal pages. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
