按特定顺序对Lucene.net搜索结果进行排序

Question

We use Lucene.Net for a product search on a website. For a category we fetch all products which have an exact match for field category with the categories unique id.

For one client we have a requirement for the products to be listed in a specific order when there are no other criteria. These are arranged per category and a product can appear in multiple categories. So we can't just have an global order field. My first thought for a solution that would work with out of the box Lucene.net was to have a field for each category on the products which will contain the sort order. But this won't scale well if there are lots of categories.

Once a search term is entered or a facet is selected we then order the products by the best match using the regular scoring system. But when there is just a term query for a category we'd like to be able to sort them by a specific order.

Is there a way of doing this with a custom scorer that could accept a list of IDs or similar and score them based on that? Essentially what we need to do is order the Lucene search results by an order specified in a database table or other external source.

Answer 1

This not an out of the box solution, we're using Open Search Server which I believe is a wrapper around the same search engine. We had similar requirements along with a whole bunch of other requirements (complex filtering/permissions/security) which drove us to cache the results from the search engine in a database (it would page through the results on a background thread and persist them to the DB), after that you can do joins between the search results and other tables in your db and do indexed sorts to your hearts content. Just a thought...

Answer 2

In a similar solution for a high traffic website, we did the sorting ourselves. Lucene would find the results, then we sorted them on the fly and gave a paged result. Most .net Sorting algorithms are efficient enough, but we used a Radix Sort ( http://en.wikipedia.org/wiki/Radix_sort ) to get it to perform to our liking.

Answer 3

I'm using Elasticsearch which is based on Lucene, and the way I'm doing it , is to boost the fields that you want the elements to be ordered by.
a Second method is pure Javascript http://isotope.metafizzy.co/ , the elements are rendered on the fly then ordered by javascript , please see some examples , It might help you! EDIT : ALL Relies on your logic : if you want to order by category : boost the category !

Scenario : user ask for category : Mobile , with normal scoring system let's say you have this results
: user looking for nokia

product1 : category :car , title: nokia car ,score :3.34
product2 : category :appliance , title : cool nokia appliance : score 3.32
product3 : category :mobile , title : Nokia 3310 : score 2.32
product4 : category :mobile , title : Nokia 6600 : score 2.31

now if the field category is boosted , You will have this :
product1 : category :mobile , title: Nokia 3310 ,score :6.35
product2 : category :mobile , title : Nokia 6600 : score 6.32
product3 : category :appliance , title : other nokia : score 2.32
product4 : category :car , title : nokia car : score 2.31

scores I used are arbitrary