Thanks. It was what I expected, but it's nice to have it confirmed. On Tue, Jul 5, 2011 at 9:39 PM, Michael McCandless < luc...@mikemccandless.com> wrote:
> This API doesn't exist today. > > Lucene has long needed for queries impls to do this, so that we can > properly plan/optimize how the query is run. EG an AND query would > use this to pick the more restrictive clause to drive the > intersection. > > For TermQuery you could just call IR.docFreq? (Doesn't take deletions > into account so it'll always be an upper bound). > > For other queries... you could pull the scorer, iterate over some > number of docs, and then "guestimate" based on what docID you got up > to vs how many docs you asked for, how many matches there would be for > the full index? This would assume matches are uniformly distributed > throughout the index (eg, that docs are indexed in random order) which > is definitely not the case typically in practice. > > Mike McCandless > > http://blog.mikemccandless.com > > On Tue, Jul 5, 2011 at 2:19 PM, Andres Taylor > <andres.tay...@neotechnology.com> wrote: > > Hi there, > > > > A work with Neo4j <http://neo4j.org/>, a NoSQL graph > > database tightly coupled with Lucene. I am now working on an optimizing > > execution engine. To do this well, I would like to know more about the > > existing Lucene indices. Ideally, I'd like to be able to ask a Lucene > index > > how many hits a query might give me, before I actually run the query. The > > answer will probably just be an estimation, but that's fine. > > > > Is this possible today? > > > > Best regards, > > > > Andrés > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > >
