Query Re-Ranking allows you to run a simple query (A) for matching documents and then re-rank the top N documents using the scores from a more complex query (B).
Since the more costly ranking from query B is only applied to the top N documents, it will have less impact on performance then just using the complex query B by itself. The trade off is that documents which score very low using the simple query A may not be considered during the re-ranking phase, even if they would score very highly using query B.
For more info see https://lucene.apache.org/solr/guide/query-re-ranking.html.
Options
Name | Type | Default value | Description |
---|---|---|---|
query | string | null | The query string for your complex ranking query. |
docs | integer | 200 | The number of top N documents from the original query that should be re-ranked. This number will be treated as a minimum, and may be increased internally automatically in order to rank enough documents to satisfy the query (i.e., start+rows). |
weight | float | 2.0 | A multiplicative factor that will be applied to the score from the reRankQuery for each of the top matching documents, before that score is added to the original score. |
Example
<?php
require(__DIR__.'/init.php');
htmlHeader();
// create a client instance
$client = new Solarium\Client($config);
// get a select query instance
$query = $client->createSelect();
$query->setQuery('electronics');
// get rerankquery component
$rerank = $query->getReRankQuery();
// boost documents that have a popularity of 10
$rerank->setQuery('popularity:10');
// set the "boost factor"
$rerank->setWeight(3);
// this executes the query and returns the result
$resultset = $client->select($query);
// display the total number of documents found by solr
echo 'NumFound: '.$resultset->getNumFound();
// show documents using the resultset iterator
foreach ($resultset as $document) {
echo '<hr/><table>';
// the documents are also iterable, to get all fields
foreach ($document as $field => $value) {
// this converts multivalue fields to a comma-separated string
if (is_array($value)) {
$value = implode(', ', $value);
}
echo '<tr><th>' . $field . '</th><td>' . $value . '</td></tr>';
}
}
htmlFooter();