[7.17] Avoid doing I/O when fetching min and max for keyword fields (#92026)

docs/changelog/92026.yaml

@@ -0,0 +1,5 @@
+pr: 92026
+summary: Avoid doing I/O when fetching min and max for keyword fields
+area: Search
+type: bug
+issues: []

server/src/main/java/org/elasticsearch/search/internal/ExitableDirectoryReader.java

@@ -127,7 +127,7 @@ static class ExitableTerms extends FilterLeafReader.FilterTerms {
 
         private final QueryCancellation queryCancellation;
 
-        private ExitableTerms(Terms terms, QueryCancellation queryCancellation) {
+        ExitableTerms(Terms terms, QueryCancellation queryCancellation) {
             super(terms);
             this.queryCancellation = queryCancellation;
         }
@@ -141,6 +141,16 @@ public TermsEnum intersect(CompiledAutomaton compiled, BytesRef startTerm) throw
         public TermsEnum iterator() throws IOException {
             return new ExitableTermsEnum(in.iterator(), queryCancellation);
         }
+
+        @Override
+        public BytesRef getMin() throws IOException {
+            return in.getMin();
+        }
+
+        @Override
+        public BytesRef getMax() throws IOException {
+            return in.getMax();
+        }
     }
 
     /**

server/src/main/java/org/elasticsearch/search/internal/FieldUsageTrackingDirectoryReader.java

@@ -85,11 +85,11 @@ public interface FieldUsageNotifier {
         void onTermVectorsUsed(String field);
     }
 
-    public static final class FieldUsageTrackingLeafReader extends SequentialStoredFieldsLeafReader {
+    static final class FieldUsageTrackingLeafReader extends SequentialStoredFieldsLeafReader {
 
         private final FieldUsageNotifier notifier;
 
-        public FieldUsageTrackingLeafReader(LeafReader in, FieldUsageNotifier notifier) {
+        FieldUsageTrackingLeafReader(LeafReader in, FieldUsageNotifier notifier) {
             super(in);
             this.notifier = notifier;
         }
@@ -230,7 +230,7 @@ public long ramBytesUsed() {
             }
         }
 
-        private class FieldUsageTrackingTerms extends FilterTerms {
+        class FieldUsageTrackingTerms extends FilterTerms {
 
             private final String field;
 
@@ -268,6 +268,16 @@ public long getSumTotalTermFreq() throws IOException {
             public long getSumDocFreq() throws IOException {
                 return in.getSumDocFreq();
             }
+
+            @Override
+            public BytesRef getMin() throws IOException {
+                return in.getMin();
+            }
+
+            @Override
+            public BytesRef getMax() throws IOException {
+                return in.getMax();
+            }
         }
 
         private class FieldUsageTrackingTermsEnum extends FilterTermsEnum {

server/src/test/java/org/elasticsearch/search/internal/ContextIndexSearcherTests.java

@@ -16,6 +16,7 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
+import org.apache.lucene.index.FilterLeafReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
@@ -24,6 +25,7 @@
 import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.BulkScorer;
@@ -270,6 +272,43 @@ public void onRemoval(ShardId shardId, Accountable accountable) {
         IOUtils.close(reader, w, dir);
     }
 
+    public void testExitableTermsMinAndMax() throws IOException {
+        Directory dir = newDirectory();
+        IndexWriter w = new IndexWriter(dir, newIndexWriterConfig(null));
+        Document doc = new Document();
+        StringField fooField = new StringField("foo", "bar", Field.Store.NO);
+        doc.add(fooField);
+        w.addDocument(doc);
+        w.flush();
+
+        DirectoryReader directoryReader = DirectoryReader.open(w);
+        for (LeafReaderContext lfc : directoryReader.leaves()) {
+            Terms terms = lfc.reader().terms("foo");
+            FilterLeafReader.FilterTerms filterTerms = new ExitableTerms(terms, new ExitableDirectoryReader.QueryCancellation() {
+                @Override
+                public boolean isEnabled() {
+                    return false;
+                }
+
+                @Override
+                public void checkCancelled() {
+
+                }
+            }) {
+                @Override
+                public TermsEnum iterator() {
+                    fail("Retrieving min and max should retrieve values from block tree instead of iterating");
+                    return null;
+                }
+            };
+            assertEquals("bar", filterTerms.getMin().utf8ToString());
+            assertEquals("bar", filterTerms.getMax().utf8ToString());
+        }
+        w.close();
+        directoryReader.close();
+        dir.close();
+    }
+
     private SparseFixedBitSet query(LeafReaderContext leaf, String field, String value) throws IOException {
         SparseFixedBitSet sparseFixedBitSet = new SparseFixedBitSet(leaf.reader().maxDoc());
         TermsEnum tenum = leaf.reader().terms(field).iterator();

server/src/test/java/org/elasticsearch/search/internal/FieldUsageTrackingDirectoryReaderTests.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.search.internal;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.TermsEnum;
+import org.apache.lucene.store.Directory;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+
+public class FieldUsageTrackingDirectoryReaderTests extends ESTestCase {
+
+    public void testTermsMinAndMax() throws IOException {
+        Directory dir = newDirectory();
+        IndexWriter w = new IndexWriter(dir, newIndexWriterConfig(null));
+        Document doc = new Document();
+        StringField fooField = new StringField("foo", "bar", Field.Store.NO);
+        doc.add(fooField);
+        w.addDocument(doc);
+        w.flush();
+
+        DirectoryReader directoryReader = DirectoryReader.open(w);
+        for (LeafReaderContext lrc : directoryReader.leaves()) {
+            FieldUsageTrackingDirectoryReader.FieldUsageTrackingLeafReader leafReader =
+                new FieldUsageTrackingDirectoryReader.FieldUsageTrackingLeafReader(lrc.reader(), new TestFieldUsageNotifier());
+            FieldUsageTrackingDirectoryReader.FieldUsageTrackingLeafReader.FieldUsageTrackingTerms terms =
+                leafReader.new FieldUsageTrackingTerms("foo", lrc.reader().terms("foo")) {
+                    @Override
+                    public TermsEnum iterator() {
+                        fail("Retrieving min and max should retrieve values from block tree instead of iterating");
+                        return null;
+                    }
+                };
+            assertEquals("bar", terms.getMin().utf8ToString());
+            assertEquals("bar", terms.getMax().utf8ToString());
+        }
+        w.close();
+        directoryReader.close();
+        dir.close();
+    }
+
+    private static class TestFieldUsageNotifier implements FieldUsageTrackingDirectoryReader.FieldUsageNotifier {
+        @Override
+        public void onTermsUsed(String field) {
+
+        }
+
+        @Override
+        public void onPostingsUsed(String field) {
+
+        }
+
+        @Override
+        public void onTermFrequenciesUsed(String field) {
+
+        }
+
+        @Override
+        public void onPositionsUsed(String field) {
+
+        }
+
+        @Override
+        public void onOffsetsUsed(String field) {
+
+        }
+
+        @Override
+        public void onDocValuesUsed(String field) {
+
+        }
+
+        @Override
+        public void onStoredFieldsUsed(String field) {
+
+        }
+
+        @Override
+        public void onNormsUsed(String field) {
+
+        }
+
+        @Override
+        public void onPayloadsUsed(String field) {
+
+        }
+
+        @Override
+        public void onPointsUsed(String field) {
+
+        }
+
+        @Override
+        public void onTermVectorsUsed(String field) {
+
+        }
+    }
+}