Re: [hibernate-dev] Coordinates storage in Lucene index for spatial functionality

maybe even simpler set a constant as the seed of your random generator: should provide a reproducible sequence of values.

>> >> On 11 May 2012 08:40, Nicolas Helleringer < nicolas.helleringer(a)gmail.com&gt; >> wrote: >> > There, back and again ... >> > >> > After fixing a bug in grid search here are some updated results on 2k >> > calls >> > >> > Degrees : >> > Mean time with Grid : 4.4897266425641025 ms. Average number of docs >> > fetched >> > : 2506.96 >> > Mean time with Grid + Distance filter : 6.4930799487179485 ms. Average >> > number of docs fetched : 425.33435897435896 >> > Mean time with DoubleRange : 14.430638703076923 ms. Average number of >> > docs >> > fetched : 542.0410256410256 >> > Mean time with DoubleRange + Distance filter : 20.483300545128206 ms. >> > Average number of docs fetched : 425.33435897435896 >> > >> > Radians : >> > Mean time with Grid : 5.650845744102564 ms. Average number of docs >> > fetched >> > : 5074.830769230769 >> > Mean time with Grid + Distance filter : 8.627138825128204 ms. Average >> > number >> > of docs fetched : 426.7902564102564 >> > Mean time with DoubleRange : 15.337755502564102 ms. Average number of >> > docs >> > fetched : 1087.705641025641 >> > Mean time with DoubleRange + Distance filter : 20.82852138769231 ms. >> > Average >> > number of docs fetched : 426.7902564102564 >> > >> > Next thing I do not explain yet is the distance filter overhead mismatch >> > : >> > It is less on grid search with more docs to test than on DoubleRange. >> > >> > Niko >> > >> > >> > 2012/5/7 Nicolas Helleringer <nicolas.helleringer(a)gmail.com&gt; >> >> >> >> Here are some results : >> >> >> >> Mean time with Grid : 4.9297471630769225 ms. Average number of docs >> >> fetched : 2416.373846153846 >> >> Mean time with Grid + Distance filter : 6.48634534 ms. Average number >> >> of >> >> docs fetched : 425.84 >> >> Mean time with DoubleRange : 15.39593650051282 ms. Average number of >> >> docs >> >> fetched : 542.72 >> >> Mean time with DoubleRange + Distance filter : 21.158394677435897 ms. >> >> Average number of docs fetched : 425.8779487179487 >> >> >> >> Sounds weird that with distance filter the two results are note the >> >> same. >> >> I shall investigate that. >> >> >> >> Niko >> >> >> >> 2012/5/7 Emmanuel Bernard <emmanuel(a)hibernate.org&gt; >> >>> >> >>> Do you know the average amount of POI that were filtered in memory but >> >>> the DistanceFilter during these runs? >> >>> >> >>> Emmanuel >> >>> >> >>> On 7 mai 2012, at 10:31, Nicolas Helleringer wrote: >> >>> >> >>> Hi all, >> >>> >> >>> I have done a radian patch/branch and some benchmarks on geonames >> >>> french >> >>> database. >> >>> >> >>> Benchs are on 2k calls each run. >> >>> >> >>> Radians: >> >>> run 1 >> >>> Mean time with Grid : 4.808043092820513 ms >> >>> Mean time with Grid + Distance filter : 6.571108878461538 ms >> >>> Mean time with DoubleRange : 14.62661525128205 ms >> >>> Mean time with DoubleRange + Distance filter : 20.143597923076925 ms >> >>> >> >>> run 2 >> >>> Mean time with Grid : 5.290368523076923 ms >> >>> Mean time with Grid + Distance filter : 6.706567517435897 ms >> >>> Mean time with DoubleRange : 14.878960702564102 ms >> >>> Mean time with DoubleRange + Distance filter : 20.75806591948718 ms >> >>> >> >>> Degrees: >> >>> run 1 >> >>> Mean time with Grid : 5.101956610769231 ms >> >>> Mean time with Grid + Distance filter : 6.548685109230769 ms >> >>> Mean time with DoubleRange : 14.767478146153845 ms >> >>> Mean time with DoubleRange + Distance filter : 20.668063972820512 ms >> >>> >> >>> run 2 >> >>> Mean time with Grid : 4.683360031282051 ms >> >>> Mean time with Grid + Distance filter : 6.7065247435897435 ms >> >>> Mean time with DoubleRange : 14.617140157948716 ms >> >>> Mean time with DoubleRange + Distance filter : 20.074868595897435 ms >> >>> >> >>> The radian branch is here for review >> >>> >> >>> : https://github.com/nicolashelleringer/hibernate-search/tree/HSEARCH-923-R... >> >>> >> >>> While moving from degrees to radians I have seen that DSL has still >> >>> some >> >>> work to do. >> >>> I shall focus on that now. >> >>> >> >>> Niko >> >>> >> >>> 2012/5/3 Sanne Grinovero <sanne(a)hibernate.org&gt; >> >>>> >> >>>> >> >>>> On May 3, 2012 10:10 AM, "Emmanuel Bernard" < emmanuel(a)hibernate.org&gt; >> >>>> wrote: >> >>>> > >> >>>> > How comes the DistanceFilter has to compute the distance for the >> >>>> > whole >> >>>> > corpus? >> >>>> >> >>>> You're right in that's not always the case, but it's possible. If >> >>>> there >> >>>> are more filters enabled and they are executed first, our filter will >> >>>> need >> >>>> to do the math only on the matched documents by the previous filters, >> >>>> but if >> >>>> there are no other constraints or filters our DistanceFilter might >> >>>> need to >> >>>> process all documents in all segments. This happens also when a limit >> >>>> is >> >>>> enabled on the collector - although limited to the current index >> >>>> segment - >> >>>> when the filter needs to be cached as it needs to evaluate each >> >>>> document in >> >>>> the segment. >> >>>> >> >>>> In our case this DistanceFilter is only applied after RangeQuery was >> >>>> applied on both longitude and latitude, so I'm not sure if this is a >> >>>> big >> >>>> problem; personally I was just wondering but I'd be fine in keeping >> >>>> this as >> >>>> a possible future improvement - but if we go for a separate issue, >> >>>> let's >> >>>> keep in mind that that the index format would not be backwards >> >>>> compatible. >> >>>> >> >>>> >> >>>> >> >>>> > By the way the actual storage (say via Hibernate ORM, or >> >>>> > Infinispan) >> >>>> > does not need to store in radian, so we don't need to do a >> >>>> > conversion when >> >>>> > reading an entity. >> >>>> >> >>>> Right, another reason to index only in whatever format makes querying >> >>>> more efficient. >> >>>> >> >>>> -- Sanne >> >>>> >> >>>> >> >>>> > >> >>>> > On 3 mai 2012, at 10:45, Sanne Grinovero wrote: >> >>>> > >> >>>> > > The reason for my comment is that the code is doing a conversion >> >>>> > > to >> >>>> > > radians in the DistanceFilter, which needs to be extremely >> >>>> > > efficient >> >>>> > > as it's not only applied on the resultset but potentially on the >> >>>> > > whole >> >>>> > > corpus of all Documents in the index. >> >>>> > > So even if it's true that conversion would be needed on the final >> >>>> > > results, we always expect people to retrieve only a limited >> >>>> > > amount >> >>>> > > of >> >>>> > > entities (like with pagination), while the index might need to >> >>>> > > perform >> >>>> > > this computation millions of times per query. >> >>>> > > >> >>>> > > If I look at the complexity of Point.getDistanceTo(double, >> >>>> > > double), >> >>>> > > I >> >>>> > > get a feeling that that method will hardly provide speedy queries >> >>>> > > because of the complex computations in it - this is just >> >>>> > > speculation >> >>>> > > at this point of course, to be sure we'd need to compare them >> >>>> > > with a >> >>>> > > large enough dataset, but it seems quite obvious that storing >> >>>> > > normalized radians should be more efficient as it would avoid a >> >>>> > > good >> >>>> > > deal of math to be executed on each Document in the index. >> >>>> > > >> >>>> > > Also if we assume people might want to use radians in their user >> >>>> > > data >> >>>> > > (I know some who definitely would never touch decimals for such a >> >>>> > > use >> >>>> > > case), there would be no need at all to convert the end result. >> >>>> > > >> >>>> > > Some more thoughts inline: >> >>>> > > >> >>>> > > On 3 May 2012 09:12, Nicolas Helleringer >> >>>> > > <nicolas.helleringer(a)gmail.com&gt; wrote: >> >>>> > >> Hi all, >> >>>> > >> >> >>>> > >> Sanne and I have been wondering about the way the spatial >> >>>> > >> branch/module/functionality for Hibernate Search shall store its >> >>>> > >> coordinates in the Lucene index. >> >>>> > >> >> >>>> > >> Today it is implemented with decimal degree for : >> >>>> > >> - easy debugging/readability >> >>>> > >> - ease of conversion on storage as we want to accept mainly >> >>>> > >> decimal >> >>>> > >> degree >> >>>> > >> from users data >> >>>> > > >> >>>> > > Valid points, but consider that "storage" is going to be way >> >>>> > > slower >> >>>> > > anyway, and typically you'll process a Document to evaluate it >> >>>> > > for a >> >>>> > > hit many many orders of magnitude more frequently than the times >> >>>> > > you >> >>>> > > store it. >> >>>> > > >> >>>> > >> >> >>>> > >> Sanne pointed out that when the search is done there is quite a >> >>>> > >> few >> >>>> > >> conversion to radians for distance calculation and suggested >> >>>> > >> that >> >>>> > >> we may >> >>>> > >> store directly coordinates under their radians form. >> >>>> > >> >> >>>> > >> I have tried a patch to implement this and as I was coding it I >> >>>> > >> feel that >> >>>> > >> the code was less readable, in the coordinates normalisation >> >>>> > >> mainly >> >>>> > >> and >> >>>> > >> that there was as many conversion as before. >> >>>> > >> Conversions had moved from search to import / export of >> >>>> > >> coordinates >> >>>> > >> in and >> >>>> > >> out the spatial module scope to user scope. >> >>>> > > >> >>>> > > I'm sure the amount of points in the code in which they are >> >>>> > > converted >> >>>> > > won't change. I'm concerned about the cardinality of the >> >>>> > > collections >> >>>> > > on which it's applied ;) >> >>>> > > "Less readable" isn't nice, but we can work on that I guess? >> >>>> > > >> >>>> > >> >> >>>> > >> What the docs does not tell (yet), is that we are waiting for >> >>>> > >> WGS >> >>>> > >> 84 (this >> >>>> > >> is a coordinate system) decimal degree coordinates input, as >> >>>> > >> these >> >>>> > >> are >> >>>> > >> quite a de facto standard (GPS output this way). >> >>>> > > >> >>>> > > How does it affect this? >> >>>> > > >> >>>> > >> >> >>>> > >> Today this is not the purpose of Hibernate Search spatial >> >>>> > >> initiative to >> >>>> > >> handle projections. There are opensource libs to handle that on >> >>>> > >> user side >> >>>> > >> very well (Proj4j) >> >>>> > >> >> >>>> > >> So. The question is : shall we store as radians or decimal >> >>>> > >> degree ? >> >>>> > >> >> >>>> > >> Niko >> >>>> > >> >> >>>> > >> P.S : Hope it is clear. If not ask for more. >> >>>> > > >> >>>> > > Thanks! >> >>>> > > Sanne >> >>>> > > _______________________________________________ >> >>>> > > hibernate-dev mailing list >> >>>> > > hibernate-dev(a)lists.jboss.org >> >>>> > > https://lists.jboss.org/mailman/listinfo/hibernate-dev >> >>>> > >> >>> >> >>> >> >>> >> >> >> > > >