Draft: Improve perf for long log lines

src/main/java/ca/pjer/logback/AsyncWorker.java

@@ -2,9 +2,7 @@
 
 import static ca.pjer.logback.AwsLogsAppender.MAX_BATCH_LOG_EVENTS;
 
-import java.util.ArrayDeque;
-import java.util.Collection;
-import java.util.Deque;
+import java.util.*;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.TimeUnit;
@@ -22,7 +20,7 @@ class AsyncWorker extends Worker implements Runnable {
     private final int maxBatchLogEvents;
     private final int discardThreshold;
     private final AtomicBoolean running;
-    private final BlockingQueue<InputLogEvent> queue;
+    private final BlockingQueue<MemoizedEvent> queue;
     private final AtomicLong lostCount;
 
     private Thread thread;
@@ -32,7 +30,7 @@ class AsyncWorker extends Worker implements Runnable {
         maxBatchLogEvents = awsLogsAppender.getMaxBatchLogEvents();
         discardThreshold = (int) Math.ceil(maxBatchLogEvents * 1.5);
         running = new AtomicBoolean(false);
-        queue = new ArrayBlockingQueue<InputLogEvent>(maxBatchLogEvents * 2);
+        queue = new ArrayBlockingQueue<>(maxBatchLogEvents * 2);
         lostCount = new AtomicLong(0);
     }
 
@@ -87,7 +85,7 @@ public void append(ILoggingEvent event) {
                 long now = System.currentTimeMillis();
                 while (now < until) {
                     try {
-                        if (!queue.offer(logEvent, until - now, TimeUnit.MILLISECONDS)) {
+                        if (!queue.offer(new MemoizedEvent(logEvent), until - now, TimeUnit.MILLISECONDS)) {
                             lostCount.incrementAndGet();
                             AwsLogsMetricsHolder.get().incrementLostCount();
                         }
@@ -104,7 +102,7 @@ public void append(ILoggingEvent event) {
             }
         } else {
             // we are not allowed to block, offer without blocking
-            if (!queue.offer(logEvent)) {
+            if (!queue.offer(new MemoizedEvent(logEvent))) {
                 lostCount.incrementAndGet();
                 AwsLogsMetricsHolder.get().incrementLostCount();
             }
@@ -160,12 +158,12 @@ private void flush(boolean all) {
     private static final int MAX_BATCH_SIZE = 1048576;
 
     private Collection<InputLogEvent> drainBatchFromQueue() {
-        Deque<InputLogEvent> batch = new ArrayDeque<InputLogEvent>(maxBatchLogEvents);
+        Deque<MemoizedEvent> batch = new ArrayDeque<>(maxBatchLogEvents);
         queue.drainTo(batch, MAX_BATCH_LOG_EVENTS);
         int batchSize = batchSize(batch);
         while (batchSize > MAX_BATCH_SIZE) {
-            InputLogEvent removed = batch.removeLast();
-            batchSize -= eventSize(removed);
+            MemoizedEvent removed = batch.removeLast();
+            batchSize -= removed.eventSize();
             if (!queue.offer(removed)) {
                 AwsLogsMetricsHolder.get().incrementBatchRequeueFailed();
                 if (getAwsLogsAppender().getVerbose()) {
@@ -175,13 +173,18 @@ private Collection<InputLogEvent> drainBatchFromQueue() {
         }
 
         AwsLogsMetricsHolder.get().incrementBatch(batchSize);
-        return batch;
+
+        List<InputLogEvent> array = new ArrayList<>(batchSize);
+        for (MemoizedEvent event : batch) {
+            array.add(event.event());
+        }
+        return array;
     }
 
-    private static int batchSize(Collection<InputLogEvent> batch) {
+    private static int batchSize(Collection<MemoizedEvent> batch) {
         int size = 0;
-        for (InputLogEvent event : batch) {
-            size += eventSize(event);
+        for (MemoizedEvent event : batch) {
+            size += event.eventSize();
         }
         return size;
     }

src/main/java/ca/pjer/logback/MemoizedEvent.java

@@ -0,0 +1,35 @@
+package ca.pjer.logback;
+
+import jdk.internal.RequiresIdentity;
+import software.amazon.awssdk.services.cloudwatchlogs.model.InputLogEvent;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
+public class MemoizedEvent {
+    // See http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutLogEvents.html
+    private static final int EVENT_SIZE_PADDING = 26;
+    private static final Charset EVENT_SIZE_CHARSET = StandardCharsets.UTF_8;
+
+    private final InputLogEvent event;
+    private byte[] messageBytes;
+
+    public MemoizedEvent(InputLogEvent event) {
+        this.event = event;
+    }
+
+    public InputLogEvent event() {
+        return event;
+    }
+
+    public byte[] getBytes() {
+        if (messageBytes == null) {
+            messageBytes = event.message().getBytes(EVENT_SIZE_CHARSET);
+        }
+        return messageBytes;
+    }
+
+    public int eventSize() {
+        return getBytes().length + EVENT_SIZE_PADDING;
+    }
+}

src/main/java/ca/pjer/logback/Worker.java

@@ -48,11 +48,11 @@ InputLogEvent asInputLogEvent(ILoggingEvent event) {
     private static final int EVENT_SIZE_PADDING = 26;
     private static final Charset EVENT_SIZE_CHARSET = Charset.forName("UTF-8");
 
-    static final int eventSize(InputLogEvent event) {
+    static int eventSize(InputLogEvent event) {
         return eventSize(event.message());
     }
 
-    static final int eventSize(String message) {
+    static int eventSize(String message) {
         return message.getBytes(EVENT_SIZE_CHARSET).length + EVENT_SIZE_PADDING;
     }