The SolrRelevancyFAQ does suggest that both index-time and search-time boosting can be used to boost the score of newer documents, but doesn't suggest what reasons/contexts one might choose one vs the other. It only provides an example of search-time boost though, so it doesn't answer the question of how to do an index time boost, if that was a question.
http://wiki.apache.org/solr/SolrRelevancyFAQ#How_can_I_boost_the_score_of_newer_documents Sorry, this doesn't answer your question, but does contribute the fact that some author of the FAQ at some point considered index-time boost not neccesarily unreasonable. ________________________________________ From: Asif Rahman [a...@newscred.com] Sent: Friday, June 04, 2010 11:31 PM To: solr-user@lucene.apache.org Subject: Re: Index-time vs. search-time boosting performance It seems like it would be far more efficient to calculate the boost factor once and store it rather than calculating it for each request in real-time. Some of our queries match tens of thousands if not hundreds of thousands of documents in a 15GB index. However, I'm not well-versed in lucene internals so I may be misunderstanding what is going on here. On Fri, Jun 4, 2010 at 8:31 PM, Jay Hill <jayallenh...@gmail.com> wrote: > I've done a lot of recency boosting to documents, and I'm wondering why you > would want to do that at index time. If you are continuously indexing new > documents, what was "recent" when it was indexed becomes, over time "less > recent". Are you unsatisfied with your current performance with the boost > function? Query-time recency boosting is a fairly common thing to do, and, > if done correctly, shouldn't be a performance concern. > > -Jay > http://lucidimagination.com > > > On Fri, Jun 4, 2010 at 4:50 PM, Asif Rahman <a...@newscred.com> wrote: > > > Perhaps I should have been more specific in my initial post. I'm doing > > date-based boosting on the documents in my index, so as to assign a > higher > > score to more recent documents. Currently I'm using a boost function to > > achieve this. I'm wondering if there would be a performance improvement > if > > instead of using the boost function at search time, I indexed the > documents > > with a date-based boost. > > > > On Fri, Jun 4, 2010 at 7:30 PM, Erick Erickson <erickerick...@gmail.com > > >wrote: > > > > > Index time boosting is different than search time boosting, so > > > asking about performance is irrelevant. > > > > > > Paraphrasing Hossman from years ago on the Lucene list (from > > > memory). > > > > > > ...index time boosting is a way of saying this documents' > > > title is more important than other documents' titles. Search > > > time boosting is a way of saying "I care about documents > > > whose titles contain this term more than other documents > > > whose titles may match other parts of this query".... > > > > > > HTH > > > Erick > > > > > > On Fri, Jun 4, 2010 at 5:10 PM, Asif Rahman <a...@newscred.com> wrote: > > > > > > > Hi, > > > > > > > > What are the performance ramifications for using a function-based > boost > > > at > > > > search time (through bf in dismax parser) versus an index-time boost? > > > > Currently I'm using boost functions on a 15GB index of ~14mm > documents. > > > > Our > > > > queries generally match many thousands of documents. I'm wondering > if > > I > > > > would see a performance improvement by switching over to index-time > > > > boosting. > > > > > > > > Thanks, > > > > > > > > Asif > > > > > > > > -- > > > > Asif Rahman > > > > Lead Engineer - NewsCred > > > > a...@newscred.com > > > > http://platform.newscred.com > > > > > > > > > > > > > > > -- > > Asif Rahman > > Lead Engineer - NewsCred > > a...@newscred.com > > http://platform.newscred.com > > > -- Asif Rahman Lead Engineer - NewsCred a...@newscred.com http://platform.newscred.com
