iter

Author: pmpailis

server/src/main/java/org/elasticsearch/action/search/QueryPhaseResultConsumer.java

@@ -18,6 +18,7 @@
 import org.elasticsearch.common.io.stream.DelayableWriteable;
 import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
 import org.elasticsearch.common.util.concurrent.AbstractRunnable;
+import org.elasticsearch.index.query.RankDocsQueryBuilder;
 import org.elasticsearch.search.SearchPhaseResult;
 import org.elasticsearch.search.SearchService;
 import org.elasticsearch.search.SearchShardTarget;
@@ -62,6 +63,7 @@ public class QueryPhaseResultConsumer extends ArraySearchPhaseResults<SearchPhas
     private final boolean hasTopDocs;
     private final boolean hasAggs;
     private final boolean performFinalReduce;
+    private final boolean isRankQuery;
 
     private final Consumer<Exception> onPartialMergeFailure;
 
@@ -116,6 +118,7 @@ public QueryPhaseResultConsumer(
         this.aggReduceContextBuilder = hasAggs ? controller.getReduceContext(isCanceled, source.aggregations()) : null;
         batchReduceSize = (hasAggs || hasTopDocs) ? Math.min(request.getBatchedReduceSize(), expectedResultSize) : expectedResultSize;
         topDocsStats = new TopDocsStats(request.resolveTrackTotalHitsUpTo());
+        isRankQuery = source != null && source.query() instanceof RankDocsQueryBuilder;
     }
 
     @Override

server/src/main/java/org/elasticsearch/search/retriever/CompoundRetrieverBuilder.java

@@ -36,6 +36,7 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
@@ -181,7 +182,8 @@ public void onResponse(MultiSearchResponse items) {
                         failures.forEach(ex::addSuppressed);
                         listener.onFailure(ex);
                     } else {
-                        results.set(combineInnerRetrieverResults(topDocs, ctx.isExplain()));
+                        RankDoc[] combinedResults = combineInnerRetrieverResults(topDocs, ctx.isExplain());
+                        results.set(normalizeRankDocs(combinedResults));
                         listener.onResponse(null);
                     }
                 }
@@ -299,6 +301,17 @@ protected SearchSourceBuilder finalizeSourceBuilder(SearchSourceBuilder sourceBu
         return sourceBuilder;
     }
 
+    private RankDoc[] normalizeRankDocs(RankDoc[] rankDocs) {
+        // normalize scores according to
+        // score = max(score, 0) + min(exp(score), 1)
+        // this maps negative numbers to (0, 1) and positive numbers to [1, inf)
+        // which is really useful as we don't want to push down negative scores
+        for (RankDoc rankDoc : rankDocs) {
+            rankDoc.score = (float) (Math.max(rankDoc.score, 0) + Math.min(Math.exp(rankDoc.score), 1));
+        }
+        return rankDocs;
+    }
+
     private RankDoc[] getRankDocs(SearchResponse searchResponse) {
         int size = searchResponse.getHits().getHits().length;
         RankDoc[] docs = new RankDoc[size];