SOLR-10480

JsonFacetPagingTest.java

import java.util.List;
import java.util.Random;
import java.util.UUID;

import org.apache.solr.client.solrj.SolrRequest.METHOD;
import org.apache.solr.client.solrj.impl.HttpSolrClient;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.common.SolrInputDocument;
import org.apache.solr.common.params.CommonParams;
import org.apache.solr.common.params.ModifiableSolrParams;
import org.apache.solr.common.params.ShardParams;
import org.apache.solr.common.util.NamedList;

public class JsonFacetPagingTest {
  public static void main(String[] args) throws Throwable {
    final String SOLR_URL = "http://localhost:8983/solr";
    JsonFacetPagingTest tests = new JsonFacetPagingTest();
    // Add docs to the core.
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate01", 0, 4);
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate02", 0, 600);
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate02", 100, 600);
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate02", 200, 600);
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate02", 300, 600);
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate02", 400, 600);
    tests.addDocumentsToCore(SOLR_URL, "fileduplicate02", 700, 800);
    //run the queries in pages.
    tests.testPaging(SOLR_URL, "fileduplicate01", 15);
  }

  protected void addDocumentsToCore(String solrURL, String coreName, int startIndex, int numberOfRecords)
      throws Exception {
    int endIndex = startIndex + numberOfRecords;
    if (numberOfRecords > 0 && endIndex > startIndex) {
      Random ran = new Random();
      HttpSolrClient client = new HttpSolrClient.Builder(solrURL).build();
      for (int index = startIndex; index <= endIndex; ++index) {
        SolrInputDocument doc = new SolrInputDocument();
        doc.addField("id", UUID.randomUUID().toString());
        doc.addField("filename", "filename-" + index);
        doc.addField("size", (1024L * ran.nextInt()));
        client.add(coreName, doc);
      }
      client.commit(coreName);
      client.close();
    }
  }

  @SuppressWarnings("unchecked")
  protected void testPaging(String solrURL, String coreName, int limit) throws Exception {
    Long offset = 0L;
    Long numBuckets = 0L;
    List<?> buckets = null;
    String facet = "{'duplicates':{'type':'terms','field':'filename','limit':%d,'offset':%d,'mincount':2,'numBuckets':true,'sort':'sum desc','facet': {'sum':'sum(size)'}}}";
    HttpSolrClient client = new HttpSolrClient.Builder(solrURL).build();
    ModifiableSolrParams params = new ModifiableSolrParams();
    params.set(CommonParams.Q, "*:*");
    params.set(CommonParams.START, String.valueOf(CommonParams.START_DEFAULT));
    params.set(CommonParams.ROWS, String.valueOf(CommonParams.START_DEFAULT));
    params.set(ShardParams.SHARDS, solrURL + "/fileduplicate01," + solrURL + "/fileduplicate02");
    do {
      params.set("json.facet", String.format(facet, limit, offset));
      QueryResponse queryResponse = client.query(coreName, params, METHOD.POST);
      if (queryResponse != null && queryResponse.getResponse() != null) {
        NamedList<Object> facets = (NamedList<Object>) queryResponse.getResponse().get("facets");
        NamedList<Object> duplicates = (NamedList<Object>) facets.get("duplicates");
        numBuckets = ((Number) duplicates.get("numBuckets")).longValue();
        buckets = (List<?>) duplicates.get("buckets");
        System.out.println(String.format("Result for Offset:%4d ==> Number of Buckets:%4d, Bucket Size:%4d, vals:%s",
            offset, numBuckets, buckets.size(), buckets));
        offset += limit;
      }
    } while (buckets != null && buckets.size() != 0 && offset <= numBuckets);
    client.close();
  }
}

Schema&Query

Schema:
  <field name="filename" type="string" indexed="true" docValues="true"/>
  <field name="id" type="string" docValues="true" indexed="true" required="true"/>
  <field name="size" type="long" indexed="true" docValues="true"/>

Create 2 cores named fileduplicate01 and fileduplicate02

Query:
http://localhost:8983/solr/fileduplicate01/select/?wt=json&q=*:*&start=0&rows=0&
shards=localhost:8983/solr/fileduplicate01,localhost:8983/solr/fileduplicate02&
json.facet={
"duplicates":{"type":"terms","field":"filename","limit":15,"offset":0,"mincount":2,"numBuckets":true,"sort":"sum
desc","facet": {"sum":"sum(size)"}}
}