Optimize sort on numeric long and date fields.

This rewrites long sort as a `DistanceFeatureQuery`, which can
efficiently skip non-competitive blocks and segments of documents.
Depending on the dataset, the speedups can be 2 - 10 times.

The optimization can be disabled with setting the system property
`es.search.rewrite_sort` to `false`.

Optimization is skipped when an index has 50% or more data with
the same value.

Optimization is done through:
1. Rewriting sort as `DistanceFeatureQuery` which can
efficiently skip non-competitive blocks and segments of documents.

2. Sorting segments according to the primary numeric sort field(#44021)
This allows to skip non-competitive segments.

3. Using collector manager.
When we optimize sort, we sort segments by their min/max value.
As a collector expects to have segments in order,
we can not use a single collector for sorted segments.
We use collectorManager, where for every segment a dedicated collector
will be created.

4. Using Lucene's shared TopFieldCollector manager
This collector manager is able to exchange minimum competitive
score between collectors, which allows us to efficiently skip
the whole segments that don't contain competitive scores.

5. When index is force merged to a single segment, #48533 interleaving
old and new segments allows for this optimization as well,
as blocks with non-competitive docs can be skipped.

Closes #37043

Co-authored-by: Jim Ferenczi <[email protected]>

Author: mayya-sharipova

buildSrc/src/main/groovy/org/elasticsearch/gradle/BuildPlugin.groovy

@@ -720,6 +720,9 @@ class BuildPlugin implements Plugin<Project> {
                 // TODO: remove this once ctx isn't added to update script params in 7.0
                 test.systemProperty 'es.scripting.update.ctx_in_params', 'false'
 
+                // TODO: remove this property in 8.0
+                test.systemProperty 'es.search.rewrite_sort', 'true'
+
                 // TODO: remove this once cname is prepended to transport.publish_address by default in 8.0
                 test.systemProperty 'es.transport.cname_in_publish_address', 'true'
 

docs/reference/search/profile.asciidoc

@@ -153,16 +153,9 @@ The API returns the following result:
                  "rewrite_time": 51443,
                  "collector": [
                     {
-                       "name": "CancellableCollector",
-                       "reason": "search_cancelled",
-                       "time_in_nanos": "304311",
-                       "children": [
-                         {
-                           "name": "SimpleTopScoreDocCollector",
-                           "reason": "search_top_hits",
-                           "time_in_nanos": "32273"
-                         }
-                       ]
+                       "name": "SimpleTopScoreDocCollector",
+                       "reason": "search_top_hits",
+                       "time_in_nanos": "32273"
                     }
                  ]
               }
@@ -445,16 +438,9 @@ Looking at the previous example:
 --------------------------------------------------
 "collector": [
    {
-      "name": "CancellableCollector",
-      "reason": "search_cancelled",
-      "time_in_nanos": "304311",
-      "children": [
-        {
-          "name": "SimpleTopScoreDocCollector",
-          "reason": "search_top_hits",
-          "time_in_nanos": "32273"
-        }
-      ]
+      "name": "SimpleTopScoreDocCollector",
+      "reason": "search_top_hits",
+      "time_in_nanos": "32273"
    }
 ]
 --------------------------------------------------
@@ -657,33 +643,26 @@ The API returns the following result:
                      "rewrite_time": 7208,
                      "collector": [
                         {
-                          "name": "CancellableCollector",
-                          "reason": "search_cancelled",
-                          "time_in_nanos": 2390,
+                          "name": "MultiCollector",
+                          "reason": "search_multi",
+                          "time_in_nanos": 1820,
                           "children": [
                             {
-                              "name": "MultiCollector",
-                              "reason": "search_multi",
-                              "time_in_nanos": 1820,
+                              "name": "FilteredCollector",
+                              "reason": "search_post_filter",
+                              "time_in_nanos": 7735,
                               "children": [
                                 {
-                                  "name": "FilteredCollector",
-                                  "reason": "search_post_filter",
-                                  "time_in_nanos": 7735,
-                                  "children": [
-                                    {
-                                      "name": "SimpleTopScoreDocCollector",
-                                      "reason": "search_top_hits",
-                                      "time_in_nanos": 1328
-                                    }
-                                  ]
-                                },
-                                {
-                                  "name": "MultiBucketCollector: [[my_scoped_agg, my_global_agg]]",
-                                  "reason": "aggregation",
-                                  "time_in_nanos": 8273
+                                  "name": "SimpleTopScoreDocCollector",
+                                  "reason": "search_top_hits",
+                                  "time_in_nanos": 1328
                                 }
                               ]
+                            },
+                            {
+                              "name": "MultiBucketCollector: [[my_scoped_agg, my_global_agg]]",
+                              "reason": "aggregation",
+                              "time_in_nanos": 8273
                             }
                           ]
                         }

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

@@ -27,6 +27,7 @@
 import org.apache.lucene.search.CollectionStatistics;
 import org.apache.lucene.search.CollectionTerminatedException;
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.ConjunctionDISI;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Explanation;
@@ -35,24 +36,31 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryCache;
 import org.apache.lucene.search.QueryCachingPolicy;
+import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.TermStatistics;
+import org.apache.lucene.search.TopFieldDocs;
+import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.BitSetIterator;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.CombinedBitSet;
 import org.apache.lucene.util.SparseFixedBitSet;
+import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
+import org.elasticsearch.search.DocValueFormat;
 import org.elasticsearch.search.dfs.AggregatedDfs;
 import org.elasticsearch.search.profile.Timer;
 import org.elasticsearch.search.profile.query.ProfileWeight;
 import org.elasticsearch.search.profile.query.QueryProfileBreakdown;
 import org.elasticsearch.search.profile.query.QueryProfiler;
 import org.elasticsearch.search.profile.query.QueryTimingType;
+import org.elasticsearch.search.query.QuerySearchResult;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
@@ -131,12 +139,86 @@ public Weight createWeight(Query query, ScoreMode scoreMode, float boost) throws
         }
     }
 
+    private void checkCancelled() {
+        if (checkCancelled != null) {
+            checkCancelled.run();
+        }
+    }
+
+    public void search(List<LeafReaderContext> leaves, Weight weight, CollectorManager manager,
+            QuerySearchResult result, DocValueFormat[] formats, TotalHits totalHits) throws IOException {
+        final List<Collector> collectors = new ArrayList<>(leaves.size());
+        for (LeafReaderContext ctx : leaves) {
+            final Collector collector = manager.newCollector();
+            searchLeaf(ctx, weight, collector);
+            collectors.add(collector);
+        }
+        TopFieldDocs mergedTopDocs = (TopFieldDocs) manager.reduce(collectors);
+        // Lucene sets shards indexes during merging of topDocs from different collectors
+        // We need to reset shard index; ES will set shard index later during reduce stage
+        for (ScoreDoc scoreDoc : mergedTopDocs.scoreDocs) {
+            scoreDoc.shardIndex = -1;
+        }
+        if (totalHits != null) { // we have already precalculated totalHits for the whole index
+            mergedTopDocs = new TopFieldDocs(totalHits, mergedTopDocs.scoreDocs, mergedTopDocs.fields);
+        }
+        result.topDocs(new TopDocsAndMaxScore(mergedTopDocs, Float.NaN), formats);
+    }
+
     @Override
     protected void search(List<LeafReaderContext> leaves, Weight weight, Collector collector) throws IOException {
-        final Weight cancellableWeight;
-        if (checkCancelled != null) {
-            cancellableWeight = new Weight(weight.getQuery()) {
+        for (LeafReaderContext ctx : leaves) { // search each subreader
+            searchLeaf(ctx, weight, collector);
+        }
+    }
+
+    /**
+     * Lower-level search API.
+     *
+     * {@link LeafCollector#collect(int)} is called for every matching document in
+     * the provided <code>ctx</code>.
+     */
+    private void searchLeaf(LeafReaderContext ctx, Weight weight, Collector collector) throws IOException {
+        checkCancelled();
+        weight = wrapWeight(weight);
+        final LeafCollector leafCollector;
+        try {
+            leafCollector = collector.getLeafCollector(ctx);
+        } catch (CollectionTerminatedException e) {
+            // there is no doc of interest in this reader context
+            // continue with the following leaf
+            return;
+        }
+        Bits liveDocs = ctx.reader().getLiveDocs();
+        BitSet liveDocsBitSet = getSparseBitSetOrNull(liveDocs);
+        if (liveDocsBitSet == null) {
+            BulkScorer bulkScorer = weight.bulkScorer(ctx);
+            if (bulkScorer != null) {
+                try {
+                    bulkScorer.score(leafCollector, liveDocs);
+                } catch (CollectionTerminatedException e) {
+                    // collection was terminated prematurely
+                    // continue with the following leaf
+                }
+            }
+        } else {
+            // if the role query result set is sparse then we should use the SparseFixedBitSet for advancing:
+            Scorer scorer = weight.scorer(ctx);
+            if (scorer != null) {
+                try {
+                    intersectScorerAndBitSet(scorer, liveDocsBitSet, leafCollector,
+                        checkCancelled == null ? () -> { } : checkCancelled);
+                } catch (CollectionTerminatedException e) {
+                    // collection was terminated prematurely
+                    // continue with the following leaf
+                }
+            }
+        }
+    }
 
+    private Weight wrapWeight(Weight weight) {
+        if (checkCancelled != null) {
+            return new Weight(weight.getQuery()) {
                 @Override
                 public void extractTerms(Set<Term> terms) {
                     throw new UnsupportedOperationException();
@@ -168,48 +250,10 @@ public BulkScorer bulkScorer(LeafReaderContext context) throws IOException {
                 }
             };
         } else {
-            cancellableWeight = weight;
+            return weight;
         }
-        searchInternal(leaves, cancellableWeight, collector);
     }
 
-    private void searchInternal(List<LeafReaderContext> leaves, Weight weight, Collector collector) throws IOException {
-        for (LeafReaderContext ctx : leaves) { // search each subreader
-            final LeafCollector leafCollector;
-            try {
-                leafCollector = collector.getLeafCollector(ctx);
-            } catch (CollectionTerminatedException e) {
-                // there is no doc of interest in this reader context
-                // continue with the following leaf
-                continue;
-            }
-            Bits liveDocs = ctx.reader().getLiveDocs();
-            BitSet liveDocsBitSet = getSparseBitSetOrNull(liveDocs);
-            if (liveDocsBitSet == null) {
-                BulkScorer bulkScorer = weight.bulkScorer(ctx);
-                if (bulkScorer != null) {
-                    try {
-                        bulkScorer.score(leafCollector, liveDocs);
-                    } catch (CollectionTerminatedException e) {
-                        // collection was terminated prematurely
-                        // continue with the following leaf
-                    }
-                }
-            } else {
-                // if the role query result set is sparse then we should use the SparseFixedBitSet for advancing:
-                Scorer scorer = weight.scorer(ctx);
-                if (scorer != null) {
-                    try {
-                        intersectScorerAndBitSet(scorer, liveDocsBitSet, leafCollector,
-                            checkCancelled == null ? () -> {} : checkCancelled);
-                    } catch (CollectionTerminatedException e) {
-                        // collection was terminated prematurely
-                        // continue with the following leaf
-                    }
-                }
-            }
-        }
-    }
 
     private static BitSet getSparseBitSetOrNull(Bits liveDocs) {
         if (liveDocs instanceof SparseFixedBitSet) {

server/src/main/java/org/elasticsearch/search/profile/query/CollectorResult.java

@@ -49,8 +49,6 @@ public class CollectorResult implements ToXContentObject, Writeable {
     public static final String REASON_SEARCH_POST_FILTER = "search_post_filter";
     public static final String REASON_SEARCH_MIN_SCORE = "search_min_score";
     public static final String REASON_SEARCH_MULTI = "search_multi";
-    public static final String REASON_SEARCH_TIMEOUT = "search_timeout";
-    public static final String REASON_SEARCH_CANCELLED = "search_cancelled";
     public static final String REASON_AGGREGATION = "aggregation";
     public static final String REASON_AGGREGATION_GLOBAL = "aggregation_global";
 

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

@@ -28,16 +28,13 @@
 import org.elasticsearch.common.lucene.MinimumScoreCollector;
 import org.elasticsearch.common.lucene.search.FilteredCollector;
 import org.elasticsearch.search.profile.query.InternalProfileCollector;
-import org.elasticsearch.tasks.TaskCancelledException;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.function.BooleanSupplier;
 
-import static org.elasticsearch.search.profile.query.CollectorResult.REASON_SEARCH_CANCELLED;
 import static org.elasticsearch.search.profile.query.CollectorResult.REASON_SEARCH_MIN_SCORE;
 import static org.elasticsearch.search.profile.query.CollectorResult.REASON_SEARCH_MULTI;
 import static org.elasticsearch.search.profile.query.CollectorResult.REASON_SEARCH_POST_FILTER;
@@ -150,18 +147,6 @@ protected InternalProfileCollector createWithProfiler(InternalProfileCollector i
         };
     }
 
-    /**
-     * Creates a collector that throws {@link TaskCancelledException} if the search is cancelled
-     */
-    static QueryCollectorContext createCancellableCollectorContext(BooleanSupplier cancelled) {
-        return new QueryCollectorContext(REASON_SEARCH_CANCELLED) {
-            @Override
-            Collector create(Collector in) throws IOException {
-                return new CancellableCollector(cancelled, in);
-            }
-        };
-    }
-
     /**
      * Creates collector limiting the collection to the first <code>numHits</code> documents
      */