Speed up LuceneTopNSourceOperator (#125622)

Author: ioanatia

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/lucene/LuceneTopNSourceOperator.java

@@ -43,8 +43,8 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-import static org.apache.lucene.search.ScoreMode.COMPLETE;
 import static org.apache.lucene.search.ScoreMode.TOP_DOCS;
+import static org.apache.lucene.search.ScoreMode.TOP_DOCS_WITH_SCORES;
 
 /**
  * Source operator that builds Pages out of the output of a TopFieldCollector (aka TopN)
@@ -65,7 +65,7 @@ public Factory(
             List<SortBuilder<?>> sorts,
             boolean scoring
         ) {
-            super(contexts, queryFunction, dataPartitioning, taskConcurrency, limit, scoring ? COMPLETE : TOP_DOCS);
+            super(contexts, queryFunction, dataPartitioning, taskConcurrency, limit, scoring ? TOP_DOCS_WITH_SCORES : TOP_DOCS);
             this.maxPageSize = maxPageSize;
             this.sorts = sorts;
         }
@@ -287,7 +287,7 @@ PerShardCollector newPerShardCollector(ShardContext shardContext, List<SortBuild
             SortField[] sortFields = sortAndFormats.get().sort.getSort();
             if (sortFields != null && sortFields.length == 1 && sortFields[0].needsScores() && sortFields[0].getReverse() == false) {
                 // SORT _score DESC
-                return new ScoringPerShardCollector(shardContext, new TopScoreDocCollectorManager(limit, null, limit).newCollector());
+                return new ScoringPerShardCollector(shardContext, new TopScoreDocCollectorManager(limit, null, 0).newCollector());
             } else {
                 // SORT ..., _score, ...
                 var sort = new Sort();
@@ -297,7 +297,7 @@ PerShardCollector newPerShardCollector(ShardContext shardContext, List<SortBuild
                     l.add(SortField.FIELD_SCORE);
                     sort = new Sort(l.toArray(SortField[]::new));
                 }
-                return new ScoringPerShardCollector(shardContext, new TopFieldCollectorManager(sort, limit, null, limit).newCollector());
+                return new ScoringPerShardCollector(shardContext, new TopFieldCollectorManager(sort, limit, null, 0).newCollector());
             }
         }
     }

x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/lucene/LuceneTopNSourceOperatorScoringTests.java

@@ -110,15 +110,16 @@ public Optional<SortAndFormats> buildSort(List<SortBuilder<?>> sorts) {
     @Override
     protected Matcher<String> expectedToStringOfSimple() {
         return matchesRegex(
-            "LuceneTopNSourceOperator\\[shards = \\[test], maxPageSize = \\d+, limit = 100, scoreMode = COMPLETE, sorts = \\[\\{.+}]]"
+            "LuceneTopNSourceOperator\\[shards = \\[test], "
+                + "maxPageSize = \\d+, limit = 100, scoreMode = TOP_DOCS_WITH_SCORES, sorts = \\[\\{.+}]]"
         );
     }
 
     @Override
     protected Matcher<String> expectedDescriptionOfSimple() {
         return matchesRegex(
-            "LuceneTopNSourceOperator"
-                + "\\[dataPartitioning = (DOC|SHARD|SEGMENT), maxPageSize = \\d+, limit = 100, scoreMode = COMPLETE, sorts = \\[\\{.+}]]"
+            "LuceneTopNSourceOperator\\[dataPartitioning = (DOC|SHARD|SEGMENT), "
+                + "maxPageSize = \\d+, limit = 100, scoreMode = TOP_DOCS_WITH_SCORES, sorts = \\[\\{.+}]]"
         );
     }
 

x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/lucene/LuceneTopNSourceOperatorTests.java

@@ -114,15 +114,15 @@ public Optional<SortAndFormats> buildSort(List<SortBuilder<?>> sorts) {
 
     @Override
     protected Matcher<String> expectedToStringOfSimple() {
-        var s = scoring ? "COMPLETE" : "TOP_DOCS";
+        var s = scoring ? "TOP_DOCS_WITH_SCORES" : "TOP_DOCS";
         return matchesRegex(
             "LuceneTopNSourceOperator\\[shards = \\[test], maxPageSize = \\d+, limit = 100, scoreMode = " + s + ", sorts = \\[\\{.+}]]"
         );
     }
 
     @Override
     protected Matcher<String> expectedDescriptionOfSimple() {
-        var s = scoring ? "COMPLETE" : "TOP_DOCS";
+        var s = scoring ? "TOP_DOCS_WITH_SCORES" : "TOP_DOCS";
         return matchesRegex(
             "LuceneTopNSourceOperator"
                 + "\\[dataPartitioning = (DOC|SHARD|SEGMENT), maxPageSize = \\d+, limit = 100, scoreMode = "