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From: Apache Wiki <wikidiffs@apache.org>
To: solr-commits@lucene.apache.org
Date: Fri, 12 Jun 2009 15:39:29 -0000
Message-ID: <20090612153929.22454.53715@eos.apache.org>
Subject: [Solr Wiki] Update of "FilterQueryGuidance" by ShalinMangar

Dear Wiki user,

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The following page has been changed by ShalinMangar:
http://wiki.apache.org/solr/FilterQueryGuidance

The comment on the change is:
Added notes on analysis, scoring and faceting

------------------------------------------------------------------------------
  Anyway, we need to analyze, to decompose the queries we want our system to handle.
  We'll then know the query parts and the frequency of the various combinations,
  and we'll then see what are good filter query candidates.
+ 
+ == Analysis, Scoring and Faceting ==
+ 
+ Each field type in Solr can define a index-time and query-time analyzer. When a query is specified through the 'q' parameter, it is parsed and the token is analyzed through the query-time analyzer for that field's type. For example, 'string' type fields are not analyzer but 'text' type fields are analyzed. However, any query specified as a filter query through the 'fq' parameter is *not* analyzed regardless of the field's type. Therefore, filter queries are best suited for filtering on exact matches or range searches. If you need to filter but the search query needs to be analyzed, it should be specified through the 'q' parameter.
+ 
+ Filter queries, as the name suggest, are used for filtering (or drilling down) the result set. Therefore, the results of a filter does not need to be ordered and hence it does not participate in the scoring. Queries specified in the 'q' parameter contribute to the scores.
+ 
+ Filter queries are great for filtering result sets based on facets. Faceting is performed on the indexed tokens and therefore the value of any facet can be directly used in the 'fq' parameter since it does not need to be analyzed.
  
  == An example to illustrate the greater efficiency obtainable by filtering ==