[GitHub] tonysun83 opened a new pull request #471: Use efficient set storage for field names

[gi...@git.apache.org]

tonysun83 opened a new pull request #471: Use efficient set storage for field names
URL: https://github.com/apache/couchdb/pull/471
 
 
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   ## Overview
   When indexing a set of fields for text search, we also create a special
   field called $fieldnames. It contains values for all the fields that
   need to be indexed. In order to do that, we need a unique list of the
   form [[<<"$fieldnames">>, Name, []] | Rest]. The old code would add an
   element to the list, and then check for membership via lists:member/2.
   This is inefficient. Some documents can contain a large number of
   fields, so we will use gb_sets to create a unique set of fields, and
   then extract out the field names.
   
   
   ## Testing recommendations
   There are no usability changes for the user as this is a performance enhancement. A full regression should be sufficient. It requires https://github.com/cloudant-labs/dreyfus to be installed.
    
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   ## JIRA issue number
   COUCHDB-3358
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   ## Related Pull Requests
   
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        repositories please list here links to those pull requests.  -->
   
   ## Checklist
   
   - [ ] Code is written and works correctly;
   - [ ] Changes are covered by tests;
   - [ ] Documentation reflects the changes;
   - [ ] I will not forget to update [rebar.config.script](https://github.com/apache/couchdb/blob/master/rebar.config.script)
         with the correct commit hash once this PR get merged.
   
 
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