Merge pull request #5599 from getsentry/perf/sdk-overhead-reduction-contexts-key-array

perf(core): [SDK Overhead Reduction 8] Reduce context serialization allocations

Author: adinauer

CHANGELOG.md

@@ -4,13 +4,11 @@
 
 ### Internal
 
-<<<<<<< perf/sdk-overhead-reduction-breadcrumb-lazy-data
+- Reduce context serialization overhead by sorting key snapshots with arrays instead of temporary lists. ([#5599](https://github.com/getsentry/sentry-java/pull/5599))
 - Reduce breadcrumb allocation overhead by creating the `Breadcrumb` data map only when data is added. ([#5598](https://github.com/getsentry/sentry-java/pull/5598))
-=======
 - Reduce JSON serialization overhead by lowering the initial `JsonWriter` nesting stack size while preserving on-demand growth. ([#5591](https://github.com/getsentry/sentry-java/pull/5591))
 - Reduce timestamp helper overhead by replacing unnecessary `Calendar` usage in `DateUtils` with direct `Date` creation. ([#5589](https://github.com/getsentry/sentry-java/pull/5589))
 - Reduce Android startup overhead by using the default timezone directly on older devices or when no timezone info is available in the locale. ([#5587](https://github.com/getsentry/sentry-java/pull/5587))
->>>>>>> perf/sdk-overhead-reduction
 
 ## 8.45.0
 

sentry/api/sentry.api

@@ -7619,6 +7619,7 @@ public final class io/sentry/util/CollectionUtils {
 	public static fun newHashMap (Ljava/util/Map;)Ljava/util/Map;
 	public static fun reverseListIterator (Ljava/util/concurrent/CopyOnWriteArrayList;)Ljava/util/ListIterator;
 	public static fun size (Ljava/lang/Iterable;)I
+	public static fun toSortedStringArray (Ljava/util/Enumeration;I)[Ljava/lang/String;
 }
 
 public abstract interface class io/sentry/util/CollectionUtils$Mapper {

sentry/src/main/java/io/sentry/MonitorContexts.java

@@ -1,10 +1,9 @@
 package io.sentry;
 
+import io.sentry.util.CollectionUtils;
 import io.sentry.util.Objects;
 import io.sentry.vendor.gson.stream.JsonToken;
 import java.io.IOException;
-import java.util.Collections;
-import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -49,8 +48,7 @@ public void serialize(final @NotNull ObjectWriter writer, final @NotNull ILogger
       throws IOException {
     writer.beginObject();
     // Serialize in alphabetical order to keep determinism.
-    final List<String> sortedKeys = Collections.list(keys());
-    Collections.sort(sortedKeys);
+    final String[] sortedKeys = CollectionUtils.toSortedStringArray(keys(), size());
     for (final String key : sortedKeys) {
       final Object value = get(key);
       if (value != null) {

sentry/src/main/java/io/sentry/protocol/Contexts.java

@@ -10,14 +10,13 @@
 import io.sentry.ProfileContext;
 import io.sentry.SpanContext;
 import io.sentry.util.AutoClosableReentrantLock;
+import io.sentry.util.CollectionUtils;
 import io.sentry.util.HintUtils;
 import io.sentry.util.Objects;
 import io.sentry.vendor.gson.stream.JsonToken;
 import java.io.IOException;
-import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -302,8 +301,7 @@ public void serialize(final @NotNull ObjectWriter writer, final @NotNull ILogger
       throws IOException {
     writer.beginObject();
     // Serialize in alphabetical order to keep determinism.
-    final List<String> sortedKeys = Collections.list(keys());
-    Collections.sort(sortedKeys);
+    final String[] sortedKeys = CollectionUtils.toSortedStringArray(keys(), internalStorage.size());
     for (final String key : sortedKeys) {
       final Object value = get(key);
       if (value != null) {

sentry/src/main/java/io/sentry/util/CollectionUtils.java

@@ -1,7 +1,9 @@
 package io.sentry.util;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
+import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.List;
 import java.util.ListIterator;
@@ -15,9 +17,28 @@
 /** Util class for Collections */
 @ApiStatus.Internal
 public final class CollectionUtils {
+  private static final String[] EMPTY_STRINGS = new String[0];
 
   private CollectionUtils() {}
 
+  public static @NotNull String[] toSortedStringArray(
+      final @NotNull Enumeration<String> source, final int size) {
+    String[] sorted = size == 0 ? EMPTY_STRINGS : new String[size];
+    int index = 0;
+    while (source.hasMoreElements()) {
+      if (index == sorted.length) {
+        sorted = Arrays.copyOf(sorted, sorted.length + 1);
+      }
+      sorted[index] = source.nextElement();
+      index++;
+    }
+    if (index != sorted.length) {
+      sorted = Arrays.copyOf(sorted, index);
+    }
+    Arrays.sort(sorted);
+    return sorted;
+  }
+
   /**
    * Returns an Iterator size
    *

sentry/src/test/java/io/sentry/MonitorContextsTest.kt

@@ -0,0 +1,19 @@
+package io.sentry
+
+import io.sentry.protocol.SerializationUtils
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import org.mockito.kotlin.mock
+
+class MonitorContextsTest {
+  @Test
+  fun `serializes entries in alphabetical order`() {
+    val contexts =
+      MonitorContexts().apply {
+        put("b", 2)
+        put("a", 1)
+      }
+
+    assertEquals("{\"a\":1,\"b\":2}", SerializationUtils.serializeToString(contexts, mock()))
+  }
+}