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Posted to issues@lucene.apache.org by GitBox <gi...@apache.org> on 2021/08/15 06:00:18 UTC

[GitHub] [lucene] zacharymorn commented on a change in pull request #240: LUCENE-10002: Deprecate IndexSearch#search(Query, Collector) in favor of IndexSearcher#search(Query, CollectorManager)

zacharymorn commented on a change in pull request #240:
URL: https://github.com/apache/lucene/pull/240#discussion_r689035631



##########
File path: lucene/core/src/java/org/apache/lucene/search/TopFieldCollectorManager.java
##########
@@ -0,0 +1,141 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.lucene.search;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Create a TopFieldCollectorManager which uses a shared hit counter to maintain number of hits and
+ * a shared {@link MaxScoreAccumulator} to propagate the minimum score across segments if the
+ * primary sort is by relevancy.
+ *
+ * <p>Note that a new collectorManager should be created for each search due to its internal states.
+ */
+public class TopFieldCollectorManager implements CollectorManager<TopFieldCollector, TopFieldDocs> {
+  private final Sort sort;
+  private final int numHits;
+  private final FieldDoc after;
+  private final HitsThresholdChecker hitsThresholdChecker;
+  private final MaxScoreAccumulator minScoreAcc;
+  private final List<TopFieldCollector> collectors;
+
+  public TopFieldCollectorManager(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold) {
+    if (totalHitsThreshold < 0) {
+      throw new IllegalArgumentException(
+          "totalHitsThreshold must be >= 0, got " + totalHitsThreshold);
+    }
+
+    this.sort = sort;
+    this.numHits = numHits;
+    this.after = after;
+    /*
+    nocommit
+    Should the following two be passed in instead? Possible custom initialization based on executor status and slices?
+    On the other hand, in a single-threaded environment, shared HitsThresholdChecker and MaxScoreAccumulator should be fast without lock contention anyway?

Review comment:
       Thanks for the great suggestion! I just ran luceneutil, and it turns out that the changes do get slower due to this thread-safe `HitsThresholdChecker` (confirmed by playing with the atomic long inside a bit). Here is the full benchmark result: 
   
   ```
                       TaskQPS baseline      StdDevQPS my_modified_version      StdDev                Pct diff p-value
       HighTermTitleBDVSort       52.86     (14.0%)       42.72      (6.6%)  -19.2% ( -34% -    1%) 0.000
          HighTermMonthSort       31.66     (10.7%)       25.90      (6.3%)  -18.2% ( -31% -   -1%) 0.000
      HighTermDayOfYearSort       24.00     (15.7%)       20.02      (8.5%)  -16.6% ( -35% -    9%) 0.000
                 TermDTSort       20.22      (9.0%)       17.13      (6.6%)  -15.3% ( -28% -    0%) 0.000
                    MedTerm     1270.02      (3.9%)     1208.29      (5.1%)   -4.9% ( -13% -    4%) 0.001
                   HighTerm      941.14      (4.0%)      900.05      (5.9%)   -4.4% ( -13% -    5%) 0.006
               OrHighNotMed      531.63      (5.6%)      514.68      (6.2%)   -3.2% ( -14% -    9%) 0.089
                    LowTerm     1112.50      (5.1%)     1081.48      (6.2%)   -2.8% ( -13% -    8%) 0.118
                MedSpanNear       12.50      (2.2%)       12.18      (2.2%)   -2.5% (  -6% -    1%) 0.000
               HighSpanNear       12.82      (1.7%)       12.52      (1.7%)   -2.4% (  -5% -    1%) 0.000
               OrHighNotLow      562.50      (6.9%)      550.15      (5.6%)   -2.2% ( -13% -   11%) 0.269
              OrHighNotHigh      577.10      (5.6%)      565.51      (6.7%)   -2.0% ( -13% -   10%) 0.303
              OrNotHighHigh      633.91      (6.7%)      621.85      (6.0%)   -1.9% ( -13% -   11%) 0.345
       HighIntervalsOrdered        6.94      (3.1%)        6.81      (3.2%)   -1.9% (  -7% -    4%) 0.061
                   PKLookup      174.06      (4.2%)      171.17      (4.5%)   -1.7% (  -9% -    7%) 0.230
                  OrHighLow      283.56      (5.3%)      279.05      (5.8%)   -1.6% ( -12% -   10%) 0.365
        MedIntervalsOrdered       19.00      (3.7%)       18.74      (3.6%)   -1.4% (  -8% -    6%) 0.237
                     Fuzzy1       59.38     (11.6%)       58.65     (12.0%)   -1.2% ( -22% -   25%) 0.740
           HighSloppyPhrase       12.68      (2.7%)       12.53      (2.1%)   -1.1% (  -5% -    3%) 0.135
                     Fuzzy2       63.95      (8.6%)       63.40      (9.0%)   -0.9% ( -17% -   18%) 0.759
            MedSloppyPhrase       17.53      (2.7%)       17.38      (2.2%)   -0.8% (  -5% -    4%) 0.279
            LowSloppyPhrase       23.90      (3.0%)       23.70      (2.8%)   -0.8% (  -6% -    5%) 0.354
                    Respell       39.23      (3.1%)       38.90      (3.1%)   -0.8% (  -6% -    5%) 0.403
                 AndHighMed       61.17      (3.8%)       60.72      (3.8%)   -0.7% (  -8% -    7%) 0.542
                  OrHighMed       48.81      (3.0%)       48.46      (3.0%)   -0.7% (  -6% -    5%) 0.444
        LowIntervalsOrdered       14.64      (2.3%)       14.55      (2.3%)   -0.6% (  -5% -    4%) 0.380
                LowSpanNear       11.65      (1.6%)       11.57      (1.6%)   -0.6% (  -3% -    2%) 0.223
                AndHighHigh       16.57      (3.6%)       16.46      (4.0%)   -0.6% (  -7% -    7%) 0.608
                     IntNRQ       17.25     (28.0%)       17.17     (27.3%)   -0.5% ( -43% -   76%) 0.959
                 OrHighHigh        9.28      (2.5%)        9.24      (2.5%)   -0.4% (  -5% -    4%) 0.635
                  MedPhrase       72.99      (3.3%)       72.75      (3.7%)   -0.3% (  -7% -    6%) 0.763
                  LowPhrase       78.02      (3.5%)       77.77      (4.0%)   -0.3% (  -7% -    7%) 0.786
      BrowseMonthSSDVFacets        3.19      (1.8%)        3.19      (1.7%)   -0.2% (  -3% -    3%) 0.653
   BrowseDayOfYearSSDVFacets        3.01      (1.5%)        3.01      (1.2%)   -0.0% (  -2% -    2%) 0.991
                   Wildcard       27.98      (2.8%)       27.98      (2.7%)    0.0% (  -5% -    5%) 0.981
                 AndHighLow      454.42      (5.4%)      455.10      (4.6%)    0.1% (  -9% -   10%) 0.925
                 HighPhrase      289.77      (5.1%)      290.54      (4.0%)    0.3% (  -8% -    9%) 0.854
               OrNotHighLow      521.43      (6.5%)      523.38      (5.7%)    0.4% ( -11% -   13%) 0.846
                    Prefix3       39.82      (4.8%)       40.02      (3.1%)    0.5% (  -7% -    8%) 0.707
               OrNotHighMed      560.49      (5.8%)      563.51      (5.5%)    0.5% ( -10% -   12%) 0.762
      BrowseMonthTaxoFacets        0.99      (4.8%)        1.00      (4.6%)    0.6% (  -8% -   10%) 0.702
       BrowseDateTaxoFacets        0.94      (4.6%)        0.94      (4.6%)    0.6% (  -8% -   10%) 0.683
   BrowseDayOfYearTaxoFacets        0.94      (4.5%)        0.94      (4.5%)    0.7% (  -7% -   10%) 0.638
   
   ```
   
   To fix the performance regression, but still try to keep the logic simple then, I'm considering adding an additional flag `supportsConcurrency` to the collector managers' constructor like such:
   
   ```
   public TopScoreDocCollectorManager(int numHits, ScoreDoc after, int totalHitsThreshold, boolean supportsConcurrency) {
       ...
       this.hitsThresholdChecker = supportsConcurrency ? 
           HitsThresholdChecker.createShared(Math.max(totalHitsThreshold, numHits)) : 
           HitsThresholdChecker.create(Math.max(totalHitsThreshold, numHits));
       this.minScoreAcc = supportsConcurrency ? new MaxScoreAccumulator() : null;
     }
   
   public TopFieldCollectorManager(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold, boolean supportsConcurrency) {
      ...
       this.hitsThresholdChecker = supportsConcurrency ? 
           HitsThresholdChecker.createShared(Math.max(totalHitsThreshold, numHits)) : 
           HitsThresholdChecker.create(Math.max(totalHitsThreshold, numHits));
       this.minScoreAcc = supportsConcurrency ? new MaxScoreAccumulator() : null;
     }
   ```
   
   What do you think about this approach?
   
   




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