Solr Snowball stemmer is inconsistent with Spanish

StackOverflow https://stackoverflow.com/questions/8386515

  •  28-10-2019
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Question

I have this stemmed field:

<fieldtype name="textes" class="solr.TextField">
  <analyzer type="index">
    <tokenizer class="solr.WhitespaceTokenizerFactory"/>
    <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="1" catenateNumbers="1" catenateAll="0" splitOnCaseChange="1"/>
    <filter class="solr.LowerCaseFilterFactory"/>
    <filter class="solr.StopFilterFactory" ignoreCase="true" words="stopwords-es.txt" enablePositionIncrements="true"/>
    <filter class="solr.SnowballPorterFilterFactory" language="Spanish" protected="protwords-es.txt"/>
  </analyzer>
  <analyzer type="query">
    <tokenizer class="solr.WhitespaceTokenizerFactory"/>
    <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="1" catenateNumbers="1" catenateAll="0" splitOnCaseChange="1"/>
    <filter class="solr.LowerCaseFilterFactory"/>
    <filter class="solr.StopFilterFactory" ignoreCase="true" words="stopwords.txt" enablePositionIncrements="true"/>
    <filter class="solr.SnowballPorterFilterFactory" language="Spanish" protected="protwords-es.txt"/>
  </analyzer>
</fieldtype>

The expected result of the search query alquileres (rents) would be a match of alquiler (rent). But when I go to "Field Analysis" in the Solr Admin site, and check an index value of alquiler and a query value of alquileres, the following happens:

  • When indexing alquiler, it gets stemmed into alquil.
  • When querying alquileres, it gets stemmed into alquiler.

So the simple case of searching the plural form of a word (alquileres) would not match its singular form (alquiler).

Shouldn't both the index and the query be stemmed into the same stem (either alquiler or alquil)? Is this a limitation of the algorithm or a misunderstanding/misconfiguration from my part?

Was it helpful?

Solution

Snowball stemming is very limited... You'd get better result by using a dictionary (Hunspell stemmer) : http://wiki.apache.org/solr/Hunspell

OTHER TIPS

This link works properly for alquileres

http://www.molinolabs.com/lematizador.html#alquileres

I use hunspell from openoffice and it does an excelent job.

My example:

URL-Elastic/_analyze?analyzer=es_AR&text=alquileres

And return: 

{
  tokens:
  [
    {
      token: "alquiler",
      start_offset: 0,
      end_offset: 10,
      type: "<ALPHANUM>",
      position: 1
    }
  ]

}

Link: https://www.openoffice.org/download/index.html

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