Address comment

Author: nodece

pulsar-broker/src/main/java/org/apache/pulsar/broker/delayed/InMemoryDelayedDeliveryTracker.java

@@ -241,13 +241,14 @@ public NavigableSet<Position> getScheduledMessages(int maxMessages) {
                     memoryUsage.addAndGet(-entryIds.getLongSizeInBytes());
                     ledgerIdToDelete.add(ledgerId);
                 } else {
+                    long oldSize = entryIds.getLongSizeInBytes();
                     Roaring64Bitmap entryIdsToRemove = new Roaring64Bitmap();
                     entryIds.stream().limit(n).forEach(entryId -> {
                         positions.add(PositionFactory.create(ledgerId, entryId));
                         entryIdsToRemove.addLong(entryId);
                     });
-                    memoryUsage.addAndGet(entryIds.getLongSizeInBytes() - oldSize);
                     entryIds.andNot(entryIdsToRemove);
+                    memoryUsage.addAndGet(entryIds.getLongSizeInBytes() - oldSize);
                     delayedMessagesCount.addAndGet(-n);
                     n = 0;
                 }

pulsar-broker/src/main/java/org/apache/pulsar/broker/delayed/bucket/BucketDelayedMessageIndexStats.java

@@ -59,7 +59,7 @@ enum Type {
     public BucketDelayedMessageIndexStats() {
     }
 
-    public Map<String, TopicMetricBean> genTopicMetricMap() {
+    public synchronized Map<String, TopicMetricBean> genTopicMetricMap() {
         Map<String, TopicMetricBean> metrics = new HashMap<>();
 
         metrics.put(BUCKET_TOTAL_NAME,