Counting in Solr

Question

I am storing the following document in Solr:

  doc {
    id: string; // this is a unique string that looks like an md5 result
    job_id: string; // this also looks like an md5 result -- this is not unique
    doc_id: number; // this is a long number -- this is not unique
    text: string; // this is stored, indexed text -- this is not unique
  }

Now what I want to do is count the number of docs (doc_id) that have the text foo in them. So if this was SQL I would want to issue something like this:

SELECT count(distinct doc_id)
FROM Doc
WHERE text like '%foo%';

Thanks in advance.

Answer 1

To make it work (using Result Grouping/Filed collapsing) you need some conditions to fulfil.

• You have to make your text query ("%foo%") to work in regular search
• doc_id have to be string, you can have copy of that field and call it doc_id_str

Then you can make request like that:

/select/?q=foo&rows=0&group=true&group.field=doc_id_str&group.limit=0&group.ngroups&group.format=simple&wt=json

This query works for me. How would it work for you, depends on your index and size of it. Please ask if you need some more guidance.

Answer 2

Similar operation to count (distinct fieldName) is not possible in Solr right now. There are issues (SOLR-1814 and SOLR-2242) related to this problem in Jira. Maybe reading comments in the issues will help you.