It is already possible. Just use fl=field(my_dv_field) or with an alias fl=my_alias:field(my_dv_field).
The problem with fetching from DocValue automatically is that it may cause as many number of disk seeks as the number of doc value fields being retrieved. On Mon, Mar 2, 2015 at 7:38 PM, Toke Eskildsen <[email protected]> wrote: > Given a non-tokenized field that has DocValues, the primary (maybe even > only?) reason for making it stored, seems to be document retrieval. When > the goal is to construct documents, the base difference between just > returning the stored values and returning both stored and DocValued > values seems to be performance: Resolving a non-trivial amount of stored > values for each document is mostly a bulk operation, while the DocValued > ones is more random access. > > In most of our setups, search-results are divided between overviews > (classic top-10 or top-20 with most relevant documents) and expanded > views (separate page or a result box that changes size). The overviews > have few data and the expanded views have more data. The data for > overviews needs to be provided quickly (stored), whereas the expanded > views are one-document-at-a-time and thus does not have the same time > requirements (DocValue speed is fine). > > As non-trivial space (15% in an index I am investigating) can be saved > by doing DocValue without storing, would it be an idea to provide > support for retrieving DocValued fields as part of document retrieval? > > This could be done in different ways: > > * Only return stored values with fl=*. If a field is referenced > explicitly with fl=myfield and is DocValued but not stored, return > the DocValued value. > > * State that DocValued fields, that are not stored, should be returned > with a flag: resolvedv=true > > > - Toke Eskildsen, State and University Library, Denmark > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > > -- Regards, Shalin Shekhar Mangar.
