Nick,
I wish I could help more directly, but, alas, my time is compressed
and I can't shepherd facets into Solr's core just yet. Since you're
focused on a single field currently, here's how I recommend you
proceed (unless someone goes the full distance on this and makes it
more easily available):
- Set up an environment where you can add some custom code to a
Solr WAR file and deploy it. At first just subclass
StandardRequestHandler as a custom class and add in something simple
like rsp.add("test", "test") and ensure you're getting this custom
value back in the returned XML.
- Hard code in those 11 queries (for now) as TermQuery's into an
array or something.
- Then loop over all those TermQuery's and do this:
SolrIndexSearcher searcher = req.getSearcher();
for each TermQuery:
DocSet valueDocSet = searcher.getDocSet(termQuery);
long count = valueDocSet.intersectionSize(originalQuery);
rsp.add(termQuery.toString(), count);
This is all off the top of my head with some glancing at the custom
faceted request handler I created for Collex, so maybe I've
overlooked something? But overall its pretty straightforward to get
counts per field value. The question is, where do those field values
come from? This is why I suggested you hard-code those 11 queries
for now, and then when that is working you can ramp up and get those
field values dynamically from the index (which is what my code does,
but I'm still fiddling to find the best way to cache those values or
read them from the index dynamically myself). The above provides the
counts. To group actual documents by a field, you could intersect,
rather than just intersectionSize.
Erik
On Jul 6, 2006, at 7:39 AM, Nick Snels wrote:
is anybody currently working on the following item from the tasklist?
* Simple faceted browsing (grouping) support in the standard query
handler
* group by field (provide counts for each distinct value in that
field)
* group by (query1, query2, query3, query4, query5)
I had the intention of doing it myself, but my knowledge of Java
proved to
small. I had a look at DisMaxRequestHandler and the
StandardRequestHandler
and even the code of Erik Hatcher. But couldn't figure out the
flow. My
current solution is to send, in my case, 11 queries
(?indent=on&q=%2B#{query}+%2Bprovince:#{province} each with a
different
value for the parameter province. On my development machine it is fast
enough. It would be much easier if I could add a parameter, group
by and get
an xml file back with the counts. Which should be a bit faster than
sending
11 requests to get the count for each. It would be great to hear from
someone who was implemented this 'simple' grouping in Solr and
maybe give me
some pointers. Thanks.
Kind regards,
Nick Snels
