Fix NPE & empty result handling in CountOnlyQueryPhaseResultConsumer (e…

…lastic#103203)

Query results can be "null" in that they are a null instance, containing
no information from the shard. 

Additionally, if we see no results, its an empty reduce phase.

This code was introduced into 8.12, which has yet to be released, but
flagging as a bug for clarity.

docs/changelog/103203.yaml

@@ -0,0 +1,5 @@
+pr: 103203
+summary: Fix NPE & empty result handling in `CountOnlyQueryPhaseResultConsumer`
+area: Search
+type: bug
+issues: []

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

@@ -49,12 +49,17 @@ Stream<SearchPhaseResult> getSuccessfulResults() {
  public void consumeResult(SearchPhaseResult result, Runnable next) {
  assert results.contains(result.getShardIndex()) == false : "shardIndex: " + result.getShardIndex() + " is already set";
  results.add(result.getShardIndex());
+ progressListener.notifyQueryResult(result.getShardIndex(), result.queryResult());
+ // We have an empty result, track that we saw it for this shard and continue;
+ if (result.queryResult().isNull()) {
+ next.run();
+ return;
+ }
  // set the relation to the first non-equal relation
  relationAtomicReference.compareAndSet(TotalHits.Relation.EQUAL_TO, result.queryResult().getTotalHits().relation);
  totalHits.add(result.queryResult().getTotalHits().value);
  terminatedEarly.compareAndSet(false, (result.queryResult().terminatedEarly() != null && result.queryResult().terminatedEarly()));
  timedOut.compareAndSet(false, result.queryResult().searchTimedOut());
- progressListener.notifyQueryResult(result.getShardIndex(), result.queryResult());
  next.run();
  }
 
@@ -80,7 +85,7 @@ public SearchPhaseController.ReducedQueryPhase reduce() throws Exception {
  1,
  0,
  0,
- false
+ results.isEmpty()
  );
  if (progressListener != SearchProgressListener.NOOP) {
  progressListener.notifyFinalReduce(

server/src/main/java/org/elasticsearch/search/query/QuerySearchResult.java

@@ -16,6 +16,7 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
 import org.elasticsearch.core.AbstractRefCounted;
+import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.RefCounted;
 import org.elasticsearch.core.Releasable;
 import org.elasticsearch.core.Releasables;
@@ -149,6 +150,7 @@ public void terminatedEarly(boolean terminatedEarly) {
  this.terminatedEarly = terminatedEarly;
  }
 
+ @Nullable
  public Boolean terminatedEarly() {
  return this.terminatedEarly;
  }
@@ -204,10 +206,12 @@ public void setRankShardResult(RankShardResult rankShardResult) {
  this.rankShardResult = rankShardResult;
  }
 
+ @Nullable
  public RankShardResult getRankShardResult() {
  return rankShardResult;
  }
 
+ @Nullable
  public DocValueFormat[] sortValueFormats() {
  return sortValueFormats;
  }
@@ -252,6 +256,7 @@ public void aggregations(InternalAggregations aggregations) {
  hasAggs = aggregations != null;
  }
 
+ @Nullable
  public DelayableWriteable<InternalAggregations> aggregations() {
  return aggregations;
  }
@@ -455,6 +460,7 @@ public void writeToNoId(StreamOutput out) throws IOException {
  }
  }
 
+ @Nullable
  public TotalHits getTotalHits() {
  return totalHits;
  }

server/src/test/java/org/elasticsearch/action/search/CountOnlyQueryPhaseResultConsumerTests.java

@@ -0,0 +1,133 @@
+/*
+ * 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.action.search;
+
+import org.apache.lucene.search.ScoreDoc;
+import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.search.TotalHits;
+import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
+import org.elasticsearch.index.shard.ShardId;
+import org.elasticsearch.search.DocValueFormat;
+import org.elasticsearch.search.SearchShardTarget;
+import org.elasticsearch.search.aggregations.InternalAggregations;
+import org.elasticsearch.search.query.QuerySearchResult;
+import org.elasticsearch.test.ESTestCase;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class CountOnlyQueryPhaseResultConsumerTests extends ESTestCase {
+
+ public void testProgressListenerExceptionsAreCaught() throws Exception {
+ ThrowingSearchProgressListener searchProgressListener = new ThrowingSearchProgressListener();
+
+ List<SearchShard> searchShards = new ArrayList<>();
+ for (int i = 0; i < 10; i++) {
+ searchShards.add(new SearchShard(null, new ShardId("index", "uuid", i)));
+ }
+ long timestamp = randomLongBetween(1000, Long.MAX_VALUE - 1000);
+ TransportSearchAction.SearchTimeProvider timeProvider = new TransportSearchAction.SearchTimeProvider(
+ timestamp,
+ timestamp,
+ () -> timestamp + 1000
+ );
+ searchProgressListener.notifyListShards(searchShards, Collections.emptyList(), SearchResponse.Clusters.EMPTY, false, timeProvider);
+
+ CountOnlyQueryPhaseResultConsumer queryPhaseResultConsumer = new CountOnlyQueryPhaseResultConsumer(searchProgressListener, 10);
+ try {
+ AtomicInteger nextCounter = new AtomicInteger(0);
+ for (int i = 0; i < 10; i++) {
+ SearchShardTarget searchShardTarget = new SearchShardTarget("node", new ShardId("index", "uuid", i), null);
+ QuerySearchResult querySearchResult = new QuerySearchResult();
+ TopDocs topDocs = new TopDocs(new TotalHits(0, TotalHits.Relation.EQUAL_TO), new ScoreDoc[0]);
+ querySearchResult.topDocs(new TopDocsAndMaxScore(topDocs, Float.NaN), new DocValueFormat[0]);
+ querySearchResult.setSearchShardTarget(searchShardTarget);
+ querySearchResult.setShardIndex(i);
+ queryPhaseResultConsumer.consumeResult(querySearchResult, nextCounter::incrementAndGet);
+ }
+
+ assertEquals(10, searchProgressListener.onQueryResult.get());
+ queryPhaseResultConsumer.reduce();
+ assertEquals(1, searchProgressListener.onFinalReduce.get());
+ assertEquals(10, nextCounter.get());
+ } finally {
+ queryPhaseResultConsumer.decRef();
+ }
+ }
+
+ public void testNullShardResultHandling() throws Exception {
+ CountOnlyQueryPhaseResultConsumer queryPhaseResultConsumer = new CountOnlyQueryPhaseResultConsumer(SearchProgressListener.NOOP, 10);
+ try {
+ AtomicInteger nextCounter = new AtomicInteger(0);
+ for (int i = 0; i < 10; i++) {
+ SearchShardTarget searchShardTarget = new SearchShardTarget("node", new ShardId("index", "uuid", i), null);
+ QuerySearchResult querySearchResult = QuerySearchResult.nullInstance();
+ querySearchResult.setSearchShardTarget(searchShardTarget);
+ querySearchResult.setShardIndex(i);
+ queryPhaseResultConsumer.consumeResult(querySearchResult, nextCounter::incrementAndGet);
+ }
+ var reducePhase = queryPhaseResultConsumer.reduce();
+ assertEquals(0, reducePhase.totalHits().value);
+ assertEquals(TotalHits.Relation.EQUAL_TO, reducePhase.totalHits().relation);
+ assertFalse(reducePhase.isEmptyResult());
+ assertEquals(10, nextCounter.get());
+ } finally {
+ queryPhaseResultConsumer.decRef();
+ }
+ }
+
+ public void testEmptyResults() throws Exception {
+ CountOnlyQueryPhaseResultConsumer queryPhaseResultConsumer = new CountOnlyQueryPhaseResultConsumer(SearchProgressListener.NOOP, 10);
+ try {
+ var reducePhase = queryPhaseResultConsumer.reduce();
+ assertEquals(0, reducePhase.totalHits().value);
+ assertEquals(TotalHits.Relation.EQUAL_TO, reducePhase.totalHits().relation);
+ assertTrue(reducePhase.isEmptyResult());
+ } finally {
+ queryPhaseResultConsumer.decRef();
+ }
+ }
+
+ private static class ThrowingSearchProgressListener extends SearchProgressListener {
+ private final AtomicInteger onQueryResult = new AtomicInteger(0);
+ private final AtomicInteger onPartialReduce = new AtomicInteger(0);
+ private final AtomicInteger onFinalReduce = new AtomicInteger(0);
+
+ @Override
+ protected void onListShards(
+ List<SearchShard> shards,
+ List<SearchShard> skippedShards,
+ SearchResponse.Clusters clusters,
+ boolean fetchPhase,
+ TransportSearchAction.SearchTimeProvider timeProvider
+ ) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ protected void onQueryResult(int shardIndex, QuerySearchResult queryResult) {
+ onQueryResult.incrementAndGet();
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ protected void onPartialReduce(List<SearchShard> shards, TotalHits totalHits, InternalAggregations aggs, int reducePhase) {
+ onPartialReduce.incrementAndGet();
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ protected void onFinalReduce(List<SearchShard> shards, TotalHits totalHits, InternalAggregations aggs, int reducePhase) {
+ onFinalReduce.incrementAndGet();
+ throw new UnsupportedOperationException();
+ }
+ }
+}