[SOLR-8685] Different result depending on count

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: spellchecker
• Assignee: Unassigned
• Reporter: Nobuo Onodera
• Created: 17/Feb/16 10:27
• Updated: 07/Apr/17 16:13

Description

I got different result when spellcheck.count is less than 5. We expect to get "iaad" as the top of result, but actually got "iqad" as the result when spellcheck.count=1

spellcheck.count=5

<response>
<lst name="responseHeader">
<int name="status">0</int>
<int name="QTime">20</int>
</lst>
<result name="response" numFound="0" start="0" maxScore="0.0"/>
<lst name="spellcheck">
<lst name="suggestions">
<lst name="icat">
<int name="numFound">5</int>
<int name="startOffset">3</int>
<int name="endOffset">7</int>
<int name="origFreq">0</int>
<arr name="suggestion">
<lst>
<str name="word">iaad</str>
<int name="freq">1</int>
</lst>
<lst>
<str name="word">ipad</str>
<int name="freq">1</int>
</lst>
<lst>
<str name="word">iqad</str>
<int name="freq">1</int>
</lst>
<lst>
<str name="word">irad</str>
<int name="freq">1</int>
</lst>
<lst>
<str name="word">isad</str>
<int name="freq">1</int>
</lst>
</arr>
</lst>
<bool name="correctlySpelled">false</bool>
<lst name="collation">
<str name="collationQuery">to:iaad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">iaad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:ipad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">ipad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:iqad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">iqad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:irad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">irad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:isad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">isad</str>
</lst>
</lst>
</lst>
</lst>
</response>

spellcheck.count=1

<response>
<lst name="responseHeader">
<int name="status">0</int>
<int name="QTime">16</int>
</lst>
<result name="response" numFound="0" start="0" maxScore="0.0"/>
<lst name="spellcheck">
<lst name="suggestions">
<lst name="icat">
<int name="numFound">1</int>
<int name="startOffset">3</int>
<int name="endOffset">7</int>
<int name="origFreq">0</int>
<arr name="suggestion">
<lst>
<str name="word">iqad</str>
<int name="freq">1</int>
</lst>
</arr>
</lst>
<bool name="correctlySpelled">false</bool>
<lst name="collation">
<str name="collationQuery">to:iaad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">iaad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:ipad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">ipad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:iqad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">iqad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:irad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">irad</str>
</lst>
</lst>
<lst name="collation">
<str name="collationQuery">to:isad</str>
<int name="hits">1</int>
<lst name="misspellingsAndCorrections">
<str name="icat">isad</str>
</lst>
</lst>
</lst>
</lst>
</response>

As the cause, modifyRequest method in SpellcheckComponent.java force to set 5 as spellcheck.count when spellcheck.count is less than 5. Then, mergeSuggestions method in SolrSpellChecker.java discard some results following code.

      // skip the first sugQueue.size() - count elements
      for (int k=0; k < sugQueue.size() - count; k++) sugQueue.pop();