--- On Thu, 5/5/11, Sujit Pal <sujit....@comcast.net> wrote:
> From: Sujit Pal <sujit....@comcast.net> > Subject: Custom sorting based on external (database) data > To: "solr-user" <solr-user@lucene.apache.org> > Date: Thursday, May 5, 2011, 11:03 PM > Hi, > > Sorry for the possible double post, I wrote this up but had > the > incorrect sender address, so I am guessing that my previous > one is going > to be rejected by the list moderation daemon. > > I am trying to figure out options for the following > problem. I am on > Solr 1.4.1 (Lucene 2.9.1). > > I have search results which are going to be ranked by the > user (using a > thumbs up/down) and would translate to a score between -1 > and +1. > > This data is stored in a database table ( > unique_id > thumbs_up > thumbs_down > num_calls > > as the thumbs up/down component is clicked. > > We want to be able to sort the results by the following > score = > (thumbs_up - thumbs_down) / (num_calls). The unique_id > field refers to > the one referenced as <uniqueId> in the schema.xml. > > Based on the following conversation: > http://www.mail-archive.com/solr-user@lucene.apache.org/msg06322.html > > > ...my understanding is that I need to: > > 1) subclass FieldType to create my own RankFieldType. > 2) In this class I override the getSortField() method to > return my > custom FieldSortComparatorSource object. > 3) Build the custom FieldSortComparatorSource object which > returns a > custom FieldSortComparator object in newComparator(). > 4) Configure the field type of class RankFieldType > (rank_t), and a field > (called rank) of field type rank_t in schema.xml of type > RankFieldType. > 5) use sort=rank+desc to do the sort. > > My question is: is there a simpler/more performant way? The > number of > database lookups seems like its going to be pretty high > with this > approach. And its hard to believe that my problem is new, > so I am > guessing this is either part of some Solr configuration I > am missing, or > there is some other (possibly simpler) approach I am > overlooking. > > Pointers to documentation or code (or even keywords I could > google) > would be much appreciated. Looks like it can be done with http://lucene.apache.org/solr/api/org/apache/solr/schema/ExternalFileField.html and http://wiki.apache.org/solr/FunctionQuery You can dump your table into three text files. Issue a commit to load these changes. Sort by function query is available in Solr3.1 though.
