And in the case of both stored=true and docValues=true, Solr 8.x shall be choosing the optimal approach by itself?
On Wed, Nov 4, 2020 at 9:15 AM Wei <weiwan...@gmail.com> wrote: > Thanks Erick. As indexed is not necessary, and docValues is more > efficient than stored fields for function queries, so we shall go with the > following: > > 3) indexed=false, stored=false, docValues=true. > > Is my understanding correct? > > Best, > Wei > > On Wed, Nov 4, 2020 at 5:24 AM Erick Erickson <erickerick...@gmail.com> > wrote: > >> You don’t need to index the field for function queries, see: >> https://lucene.apache.org/solr/guide/8_6/docvalues.html. >> >> Function queries, as opposed to sorting, faceting and grouping are >> evaluated at search time where the >> search process is already parked on the document anyway, so answering the >> question “for doc X, what >> is the value of field Y” to compute the score. DocValues are still more >> efficient I think, although I >> haven’t measured explicitly... >> >> For sorting, faceting and grouping, it’s a much different story. Take >> sorting. You have to ask >> “for field Y, what’s the value in docX and docZ?”. Say you’re parked on >> docX. Doc Z is long gone >> and getting the value for field Y much more expensive. >> >> Also, docValues will not increase memory requirements _unless used_. >> Otherwise they’ll >> just sit there on disk. They will certainly increase disk space whether >> used or not. >> >> And _not_ using docValues when you facet, group or sort will also >> _certainly_ increase >> your heap requirements since the docValues structure must be built on the >> heap rather >> than be in MMapDirectory space. >> >> Best, >> Erick >> >> >> > On Nov 4, 2020, at 5:32 AM, uyilmaz <uyil...@vivaldi.net.INVALID> >> wrote: >> > >> > Hi, >> > >> > I'm by no means expert on this so if anyone sees a mistake please >> correct me. >> > >> > I think you need to index this field, since boost functions are added >> to the query as optional clauses ( >> https://lucene.apache.org/solr/guide/6_6/the-dismax-query-parser.html#TheDisMaxQueryParser-Thebf_BoostFunctions_Parameter). >> It's like boosting a regular field by putting ^2 next to it in a query. >> Storing or enabling docValues will unnecesarily consume space/memory. >> > >> > On Tue, 3 Nov 2020 16:10:50 -0800 >> > Wei <weiwan...@gmail.com> wrote: >> > >> >> Hi, >> >> >> >> I have a couple of primitive single value numeric type fields, their >> >> values are used in boosting functions, but not used in sort/facet. or >> in >> >> returned response. Should I use docValues for them in the schema? I >> can >> >> think of the following options: >> >> >> >> 1) indexed=true, stored=true, docValues=false >> >> 2) indexed=true, stored=false, docValues=true >> >> 3) indexed=false, stored=false, docValues=true >> >> >> >> What would be the performance implications for these options? >> >> >> >> Best, >> >> Wei >> > >> > >> > -- >> > uyilmaz <uyil...@vivaldi.net> >> >>
