The question was either non-trivial or heavily uninteresting! No replies yet :) Thankfully, I figured out a solution for the problem at hand. For people who might be looking for a solution, here it goes -
1. Extended the RandomSortField to create your own YourCustomRandomField. 2. Override the RandomSortField #getSortField method to return YourSortField. 3. Return YourSortComparatorSource from YourSortField#getFactory(). 4. Most of the rules related to the problem statement would be handled in the YourSortComparatorSource#newComparator(). 5. In your schema, create a dynamic field of YourFieldType. Pass in the "id" (Look at the problem statement in the trailing post) as a part of the dynamic field name in your sort query. 6. Inside YourSortComparatorSource#newComparator(), get the above mentioned "id" from fieldName parameter and then fetch the values indexed in this field using Lucene's FieldCache. 7. In your ScoreDocComparator#compare(), first check for the values in the "id" field and return -1,1,0 or "hash(i.doc + seed) - hash(j.doc + seed)" based on the values in this field. The idea is to only randomize results for a particular "id" value. Hoss, I have a small question (RandomSortField bears your signature) - Any reason as to why RandomSortField#hash() and RandomSortField#getSeed() methods are private? Having them public would have saved myself from "owning" a copy in my class as well. My solution applies to Solr 1.3. It might not hold true for higher versions as underlying Lucene API's might have changed. Cheers Avlesh On Sun, Sep 20, 2009 at 4:28 PM, Avlesh Singh <avl...@gmail.com> wrote: > I am using Solr 1.3 > I have a "solr.RandomSortField" type dynamic field which I use to randomize > my results. > > I am in a tricky situation. I need to randomize only "certain results" in > my Hits. > To elaborate, I have a integer field called "category_id". When performing > a query, I need to get results from all categories and place the ones from > SOME_CAT_ID at the top. I achieved this by populating a separate dynamic > field while indexing data. i.e When a doc is added to the index a field > called "dynamic_cat_id_SOME_CAT_ID" is populated with its category id. While > querying, I know the value of SOME_CAT_ID, so adding a > "sort=dynamic_cat_id_SOME_CAT_ID asc, score desc" to my query, works > absolutely fine. > > So far so good. I am now supposed to randomize the results for > category_id=SOME_CAT_ID, i.e results at the top. My understading is that > adding "sort=dynamic_cat_id_SOME_CAT_ID asc, > *my_dynamic_random_field_SOME_SEED > asc*, score desc" to the query would randomize all the results. This is > not desired. I only want to randomize the one's at the top > (category_id=SOME_CAT_ID), rest should be ordered based on relevance score. > > Two simple questions: > > 1. Is there a way to achieve this without writing any custom code? > 2. If the answer to #1 is "no", the Where should I start? I glanced the > RandomSortField class but could not figure out how to proceed. Do I need to > create a custom FieldType? Can I extend the RandomSortField and override > the > sorting behaviour? > > Any help would be appreciated. > > Cheers > Avlesh >
