On Fri, Nov 2, 2012 at 4:46 PM, Noah Misch <n...@leadboat.com> wrote:
> 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. > Sorry, didn't understand this point. What exactly do you mean by box_overlap()-style? ------ With best regards, Alexander Korotkov.
