They are _absolutely_ able to be used together. Background: “In the bad old days”, there was no docValues. So whenever you needed to facet/sort/group/use function queries Solr (well, Lucene) had to take the inverted structure resulting from “index=true” and “uninvert” it on the Java heap.
docValues essentially does the “uninverting” at index time and puts that structure in a separate file for each segment. So rather than uninvert the index on the heap, Lucene can just read it in from disk in MMapDirectory (i.e. OS) memory space. The downside is that your index will be bigger when you do both, that is the size on disk will be bigger. But, it’ll be much faster to load, much faster to autowarm, and will move the structures necessary to do faceting/sorting/etc into OS memory where the garbage collection is vastly more efficient than Javas. And frankly I don’t think the increased size on disk is a downside. You’ll have to have the memory anyway, and having it used on the OS memory space is so much more efficient than on Java’s heap that it’s a win-win IMO. Oh, and if you never sort/facet/group/use function queries, then the docValues structures are never even read into MMapDirectory space. So yes, freely do both. Best, Erick > On May 19, 2020, at 5:41 PM, matthew sporleder <msporle...@gmail.com> wrote: > > You can index AND docvalue? For some reason I thought they were exclusive > > On Tue, May 19, 2020 at 5:36 PM Erick Erickson <erickerick...@gmail.com> > wrote: >> >> Yes. You should also index them…. >> >> Here’s the way I think of it. >> >> For questions “For term X, which docs contain that value?” means index=true. >> This is a search. >> >> For questions “Does doc X have value Y in field Z”, means docValues=true. >> >> what’s the difference? Well, the first one is to get the result set. The >> second is for, given a result set, >> count/sort/whatever. >> >> fq clauses are searches, so index=true. >> >> sorting, faceting, grouping and function queries are “for each doc in the >> result set, what values does field Y contain?” >> >> Maybe that made things clear as mud, but it’s the way I think of it ;) >> >> Best, >> Erick >> >> >> >> fq clauses are searches. Indexed=true is for searching. >> >> sort >> >>> On May 19, 2020, at 4:00 PM, matthew sporleder <msporle...@gmail.com> wrote: >>> >>> I have quite a few numeric / meta-data type fields in my schema and >>> pretty much only use them in fq=, sort=, and friends. Should I always >>> use DocValue on these if i never plan to q=search: on them? Are there >>> any drawbacks? >>> >>> Thanks, >>> Matt >>
