Debugging Solr search queries on Sunspot

Question

How can I debug Solr search queries when using the Sunspot gem on Rails? I have some queries that are returning bizarrely high scores, and I'm trying to get to the bottom of why this is happening.

It doesn't seem like any debugging information is exposed to Sunspot, so I think that I need to debug through Solr directly. Fortunately, Solr has a handy web interface to search from, but for some reason, any queries I enter there return with 0 results.

For example, when I search for the word "test" on my web app, it returns plenty of hits. When I search for the same thing on the Solr admin interface this is what I get:

<response>
  <lst name="responseHeader">
    <int name="status">0</int>
    <int name="QTime">172</int>
    <lst name="params">
      <str name="explainOther"/>
      <str name="fl">*,score</str>
      <str name="indent">on</str>
      <str name="start">0</str>
      <str name="q">test</str>
      <str name="hl.fl"/>
      <str name="qt">standard</str>
      <str name="wt">standard</str>
      <str name="fq"/>
      <str name="version">2.2</str>
      <str name="rows">10</str>
    </lst>
  </lst>
  <result name="response" numFound="0" start="0" maxScore="0.0"/>
</response> 

Answer 1

When you search from your web app do you search specific fields or just the default field? When you type something into the admin console to debug searches, its easy to forget to tell it which field(s) you want to search on and if you don't tell it then only the default field is searched.

https://stackoverflow.com/a/8082936/474597 has a better explaination, in which you need to include the search column name such as body_text:your_key_words

Answer 2

If setting log_level to FINEST doesn't work, you should add this line to an initializer:

require "sunspot/rails/solr_logging"

source: http://outoftime.github.com/2010/03/03/sunspot-1-0.html

Answer 3

Try reading Debugging Search Application Relevance Issues which discusses explanations and the Solr analysis tool.

Answer 4

To debug requests sent to Solr, I often use an http request analyzer like tcpmon or fiddler.

Answer 5

Set the log level to FINEST and you will see the exact query in the log file.