Optimizing tsdb doc values codec merging

benchmarks/src/main/java/org/elasticsearch/benchmark/index/codec/tsdb/TSDBDocValuesMergeBenchmark.java

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+/*
+ * 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", the "GNU Affero General Public License v3.0 only", 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", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.benchmark.index.codec.tsdb;
+
+import org.apache.lucene.analysis.standard.StandardAnalyzer;
+import org.apache.lucene.codecs.DocValuesFormat;
+import org.apache.lucene.codecs.lucene101.Lucene101Codec;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.SortedDocValuesField;
+import org.apache.lucene.document.SortedNumericDocValuesField;
+import org.apache.lucene.document.SortedSetDocValuesField;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.SortedNumericSortField;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FSDirectory;
+import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.index.codec.tsdb.ES87TSDBDocValuesFormat;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.TearDown;
+import org.openjdk.jmh.annotations.Threads;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.profile.AsyncProfiler;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.Random;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.SampleTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Benchmark)
+@Fork(1)
+@Threads(1)
+@Warmup(iterations = 0)
+@Measurement(iterations = 1)
+public class TSDBDocValuesMergeBenchmark {
+
+    @Param("20431204")
+    private int nDocs;
+
+    @Param("1000")
+    private int deltaTime;
+
+    @Param("42")
+    private int seed;
+
+    private static final String TIMESTAMP_FIELD = "@timestamp";
+    private static final String HOSTNAME_FIELD = "host.name";
+    private static final long BASE_TIMESTAMP = 1704067200000L;
+
+    private IndexWriter indexWriterWithoutOptimizedMerge;
+    private IndexWriter indexWriterWithOptimizedMerge;
+    private ExecutorService executorService;
+
+    public static void main(String[] args) throws RunnerException {
+        final Options options = new OptionsBuilder().include(TSDBDocValuesMergeBenchmark.class.getSimpleName())
+            .addProfiler(AsyncProfiler.class)
+            .build();
+
+        new Runner(options).run();
+    }
+
+    @Setup(Level.Trial)
+    public void setup() throws IOException {
+        executorService = Executors.newSingleThreadExecutor();
+
+        final Directory tempDirectoryWithoutDocValuesSkipper = FSDirectory.open(Files.createTempDirectory("temp1-"));
+        final Directory tempDirectoryWithDocValuesSkipper = FSDirectory.open(Files.createTempDirectory("temp2-"));
+
+        indexWriterWithoutOptimizedMerge = createIndex(tempDirectoryWithoutDocValuesSkipper, false);
+        indexWriterWithOptimizedMerge = createIndex(tempDirectoryWithDocValuesSkipper, true);
+    }
+
+    private IndexWriter createIndex(final Directory directory, final boolean optimizedMergeEnabled) throws IOException {
+
+        final IndexWriterConfig config = new IndexWriterConfig(new StandardAnalyzer());
+        // NOTE: index sort config matching LogsDB's sort order
+        config.setIndexSort(
+            new Sort(
+                new SortField(HOSTNAME_FIELD, SortField.Type.STRING, false),
+                new SortedNumericSortField(TIMESTAMP_FIELD, SortField.Type.LONG, true)
+            )
+        );
+        ES87TSDBDocValuesFormat docValuesFormat = new ES87TSDBDocValuesFormat(4096, optimizedMergeEnabled);
+        config.setCodec(new Lucene101Codec() {
+
+            @Override
+            public DocValuesFormat getDocValuesFormatForField(String field) {
+                return docValuesFormat;
+            }
+        });
+
+        long counter1 = 0;
+        long counter2 = 10_000_000;
+        long[] gauge1Values = new long[] { 2, 4, 6, 8, 10, 12, 14, 16 };
+        long[] gauge2Values = new long[] { -2, -4, -6, -8, -10, -12, -14, -16 };
+        int numHosts = 1000;
+        String[] tags = new String[] { "tag_1", "tag_2", "tag_3", "tag_4", "tag_5", "tag_6", "tag_7", "tag_8" };
+
+        final Random random = new Random(seed);
+        IndexWriter indexWriter = new IndexWriter(directory, config);
+        for (int i = 0; i < nDocs; i++) {
+            final Document doc = new Document();
+
+            final int batchIndex = i / numHosts;
+            final String hostName = "host-" + batchIndex;
+            // Slightly vary the timestamp in each document
+            final long timestamp = BASE_TIMESTAMP + ((i % numHosts) * deltaTime) + random.nextInt(0, deltaTime);
+
+            doc.add(new SortedDocValuesField(HOSTNAME_FIELD, new BytesRef(hostName)));
+            doc.add(new SortedNumericDocValuesField(TIMESTAMP_FIELD, timestamp));
+            doc.add(new SortedNumericDocValuesField("counter_1", counter1++));
+            doc.add(new SortedNumericDocValuesField("counter_2", counter2++));
+            doc.add(new SortedNumericDocValuesField("gauge_1", gauge1Values[i % gauge1Values.length]));
+            doc.add(new SortedNumericDocValuesField("gauge_2", gauge2Values[i % gauge1Values.length]));
+            int numTags = tags.length % (i + 1);
+            for (int j = 0; j < numTags; j++) {
+                doc.add(new SortedSetDocValuesField("tags", new BytesRef(tags[j])));
+            }
+
+            indexWriter.addDocument(doc);
+        }
+        indexWriter.commit();
+        return indexWriter;
+    }
+
+    @Benchmark
+    public void forceMergeWithoutOptimizedMerge() throws IOException {
+        forceMerge(indexWriterWithoutOptimizedMerge);
+    }
+
+    @Benchmark
+    public void forceMergeWithOptimizedMerge() throws IOException {
+        forceMerge(indexWriterWithOptimizedMerge);
+    }
+
+    private void forceMerge(final IndexWriter indexWriter) throws IOException {
+        indexWriter.forceMerge(1);
+    }
+
+    @TearDown(Level.Trial)
+    public void tearDown() {
+        if (executorService != null) {
+            executorService.shutdown();
+            try {
+                if (executorService.awaitTermination(30, TimeUnit.SECONDS) == false) {
+                    executorService.shutdownNow();
+                }
+            } catch (InterruptedException e) {
+                executorService.shutdownNow();
+                Thread.currentThread().interrupt();
+            }
+        }
+    }
+}

docs/changelog/125403.yaml

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+pr: 125403
+summary: First step optimizing tsdb doc values codec merging
+area: Codec
+type: enhancement
+issues: []