如何限制Solr在3个字母后建议记录

Question

1. List item
2. Solr version - 6.6.0

I am adding a new field in the documents say "autocomplete" and copying data from other relevant keys.

Changes in schema.xml

<field name="autocomplete" type="text_general" indexed="true" stored="true"
multiValued="true" />

<copyField source="a" dest="autocomplete"/>
<copyField source="b" dest="autocomplete"/>
<copyField source="c" dest="autocomplete"/>
<copyField source="d" dest="autocomplete"/>

Changes in suggester of solrconfig.xml

  <searchComponent name="suggest" class="solr.SuggestComponent">
    <lst name="suggester">
      <str name="name">infixSuggester</str>
      <str name="lookupImpl">AnalyzingInfixLookupFactory</str>  
      <str name="dictionaryImpl">DocumentDictionaryFactory</str>
      <str name="field">autocomplete</str>
       <str name="contextField">type</str>
      <str name="suggestAnalyzerFieldType">text_general</str>
      <str name="buildOnStartup">false</str>
    </lst>
  </searchComponent>

I can query over it and use context filter as well.

Can I restrict it to show records only after 3 letters input?

Answer 1

Usually this is the kind of change that would be client side. You can send an API call just when you reach your configured amount of characters.

Solr side :

Unfortunately, using the analysing infix lookup strategy, it is not possible to change the min chars for the possible suggestions. This is because, when creating the possible suggestions in the auxiliary index, the minimum ngram is hardcoded to be 1 :

org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggester.java:364
TokenFilter filter = new EdgeNGramTokenFilter(components.getTokenStream(), 1, minPrefixChars);

Given N your desired amount of characters: If you really want to do that Solr side, then you can do that explicitly configuring an autocompletion field ( analysed with an edgeNgram token filter with a min value of N for the ngram).