Support semantic reranking using contextual snippets instead of entire field text (#129369)

Author: kderusso

docs/changelog/129369.yaml

@@ -0,0 +1,6 @@
+pr: 129369
+summary: Support semantic reranking using contextual snippets instead of entire field
+  text
+area: Relevance
+type: enhancement
+issues: []

qa/ccs-common-rest/src/yamlRestTest/java/org/elasticsearch/test/rest/yaml/CcsCommonYamlTestSuiteIT.java

@@ -92,7 +92,8 @@ public class CcsCommonYamlTestSuiteIT extends ESClientYamlSuiteTestCase {
         .feature(FeatureFlag.TIME_SERIES_MODE)
         .feature(FeatureFlag.SUB_OBJECTS_AUTO_ENABLED)
         .feature(FeatureFlag.IVF_FORMAT)
-        .feature(FeatureFlag.SYNTHETIC_VECTORS);
+        .feature(FeatureFlag.SYNTHETIC_VECTORS)
+        .feature(FeatureFlag.RERANK_SNIPPETS);
 
     private static ElasticsearchCluster remoteCluster = ElasticsearchCluster.local()
         .name(REMOTE_CLUSTER_NAME)

qa/ccs-common-rest/src/yamlRestTest/java/org/elasticsearch/test/rest/yaml/RcsCcsCommonYamlTestSuiteIT.java

@@ -94,6 +94,7 @@ public class RcsCcsCommonYamlTestSuiteIT extends ESClientYamlSuiteTestCase {
         .feature(FeatureFlag.SUB_OBJECTS_AUTO_ENABLED)
         .feature(FeatureFlag.IVF_FORMAT)
         .feature(FeatureFlag.SYNTHETIC_VECTORS)
+        .feature(FeatureFlag.RERANK_SNIPPETS)
         .user("test_admin", "x-pack-test-password");
 
     private static ElasticsearchCluster fulfillingCluster = ElasticsearchCluster.local()

qa/smoke-test-multinode/src/yamlRestTest/java/org/elasticsearch/smoketest/SmokeTestMultiNodeClientYamlTestSuiteIT.java

@@ -40,6 +40,7 @@ public class SmokeTestMultiNodeClientYamlTestSuiteIT extends ESClientYamlSuiteTe
         .feature(FeatureFlag.USE_LUCENE101_POSTINGS_FORMAT)
         .feature(FeatureFlag.IVF_FORMAT)
         .feature(FeatureFlag.SYNTHETIC_VECTORS)
+        .feature(FeatureFlag.RERANK_SNIPPETS)
         .build();
 
     public SmokeTestMultiNodeClientYamlTestSuiteIT(@Name("yaml") ClientYamlTestCandidate testCandidate) {

rest-api-spec/src/yamlRestTest/java/org/elasticsearch/test/rest/ClientYamlTestSuiteIT.java

@@ -40,6 +40,7 @@ public class ClientYamlTestSuiteIT extends ESClientYamlSuiteTestCase {
         .feature(FeatureFlag.USE_LUCENE101_POSTINGS_FORMAT)
         .feature(FeatureFlag.IVF_FORMAT)
         .feature(FeatureFlag.SYNTHETIC_VECTORS)
+        .feature(FeatureFlag.RERANK_SNIPPETS)
         .build();
 
     public ClientYamlTestSuiteIT(@Name("yaml") ClientYamlTestCandidate testCandidate) {

server/src/internalClusterTest/java/org/elasticsearch/search/rank/FieldBasedRerankerIT.java

@@ -193,7 +193,7 @@ public RankShardResult buildRankFeatureShardResult(SearchHits hits, int shardId)
                         RankFeatureDoc[] rankFeatureDocs = new RankFeatureDoc[hits.getHits().length];
                         for (int i = 0; i < hits.getHits().length; i++) {
                             rankFeatureDocs[i] = new RankFeatureDoc(hits.getHits()[i].docId(), hits.getHits()[i].getScore(), shardId);
-                            rankFeatureDocs[i].featureData(hits.getHits()[i].field(field).getValue().toString());
+                            rankFeatureDocs[i].featureData(List.of(hits.getHits()[i].field(field).getValue().toString()));
                         }
                         return new RankFeatureShardResult(rankFeatureDocs);
                     } catch (Exception ex) {
@@ -210,7 +210,7 @@ public RankFeaturePhaseRankCoordinatorContext buildRankFeaturePhaseCoordinatorCo
                 protected void computeScores(RankFeatureDoc[] featureDocs, ActionListener<float[]> scoreListener) {
                     float[] scores = new float[featureDocs.length];
                     for (int i = 0; i < featureDocs.length; i++) {
-                        scores[i] = Float.parseFloat(featureDocs[i].featureData);
+                        scores[i] = Float.parseFloat(featureDocs[i].featureData.get(0));
                     }
                     scoreListener.onResponse(scores);
                 }

server/src/internalClusterTest/java/org/elasticsearch/search/rank/MockedRequestActionBasedRerankerIT.java

@@ -275,7 +275,7 @@ protected void computeScores(RankFeatureDoc[] featureDocs, ActionListener<float[
                 l.onResponse(scores);
             });
 
-            List<String> featureData = Arrays.stream(featureDocs).map(x -> x.featureData).toList();
+            List<String> featureData = Arrays.stream(featureDocs).map(x -> x.featureData).flatMap(List::stream).toList();
             TestRerankingActionRequest request = generateRequest(featureData);
             try {
                 ActionType<TestRerankingActionResponse> action = actionType();

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -352,6 +352,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ESQL_SAMPLE_OPERATOR_STATUS = def(9_127_0_00);
     public static final TransportVersion ESQL_TOPN_TIMINGS = def(9_128_0_00);
     public static final TransportVersion NODE_WEIGHTS_ADDED_TO_NODE_BALANCE_STATS = def(9_129_0_00);
+    public static final TransportVersion RERANK_SNIPPETS = def(9_130_0_00);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/search/builder/SearchSourceBuilder.java

@@ -1187,9 +1187,11 @@ public SearchSourceBuilder rewrite(QueryRewriteContext context) throws IOExcepti
                 sliceBuilder,
                 sorts,
                 rescoreBuilders,
-                highlightBuilder
+                highlightBuilder,
+                rankBuilder
             )
         ));
+
         if (retrieverBuilder != null) {
             var newRetriever = retrieverBuilder.rewrite(context);
             if (newRetriever != retrieverBuilder) {
@@ -1205,6 +1207,11 @@ public SearchSourceBuilder rewrite(QueryRewriteContext context) throws IOExcepti
             }
         }
 
+        RankBuilder rankBuilder = null;
+        if (this.rankBuilder != null) {
+            rankBuilder = this.rankBuilder.rewrite(context);
+        }
+
         List<SubSearchSourceBuilder> subSearchSourceBuilders = Rewriteable.rewrite(this.subSearchSourceBuilders, context);
         QueryBuilder postQueryBuilder = null;
         if (this.postQueryBuilder != null) {
@@ -1229,7 +1236,8 @@ public SearchSourceBuilder rewrite(QueryRewriteContext context) throws IOExcepti
             || aggregations != this.aggregations
             || rescoreBuilders != this.rescoreBuilders
             || sorts != this.sorts
-            || this.highlightBuilder != highlightBuilder;
+            || this.highlightBuilder != highlightBuilder
+            || this.rankBuilder != rankBuilder;
         if (rewritten) {
             return shallowCopy(
                 subSearchSourceBuilders,
@@ -1239,7 +1247,8 @@ public SearchSourceBuilder rewrite(QueryRewriteContext context) throws IOExcepti
                 this.sliceBuilder,
                 sorts,
                 rescoreBuilders,
-                highlightBuilder
+                highlightBuilder,
+                rankBuilder
             );
         }
         return this;
@@ -1257,7 +1266,8 @@ public SearchSourceBuilder shallowCopy() {
             sliceBuilder,
             sorts,
             rescoreBuilders,
-            highlightBuilder
+            highlightBuilder,
+            rankBuilder
         );
     }
 
@@ -1274,7 +1284,8 @@ private SearchSourceBuilder shallowCopy(
         SliceBuilder slice,
         List<SortBuilder<?>> sorts,
         List<RescorerBuilder> rescoreBuilders,
-        HighlightBuilder highlightBuilder
+        HighlightBuilder highlightBuilder,
+        RankBuilder rankBuilder
     ) {
         SearchSourceBuilder rewrittenBuilder = new SearchSourceBuilder();
         rewrittenBuilder.aggregations = aggregations;

server/src/main/java/org/elasticsearch/search/fetch/subphase/highlight/HighlightBuilder.java

@@ -399,7 +399,7 @@ public Field(String name) {
             this.name = name;
         }
 
-        private Field(Field template, QueryBuilder builder) {
+        Field(Field template, QueryBuilder builder) {
             super(template, builder);
             name = template.name;
             fragmentOffset = template.fragmentOffset;