[GitHub] [pulsar] codelipenghui commented on a change in pull request #14727: when consumer close and create frequently, delay message will be duplicated

[GitBox <gi...@apache.org>]

codelipenghui commented on a change in pull request #14727:
URL: https://github.com/apache/pulsar/pull/14727#discussion_r828799516



##########
File path: pulsar-broker/src/main/java/org/apache/pulsar/broker/delayed/InMemoryDelayedDeliveryTracker.java
##########
@@ -78,6 +83,17 @@ public boolean addMessage(long ledgerId, long entryId, long deliveryAt) {
             return false;
         }
 
+        synchronized (this) {
+            if (ComparisonChain.start().compare(ledgerId, lastLedgerId).compare(entryId, lastEntryId).result() <= 0) {
+                if (log.isWarnEnabled()) {
+                    log.warn("[{}] Add message  {}:{}  less than last {} {} ", dispatcher.getName(), ledgerId, entryId,

Review comment:
       The info log is ok here since it's expected behavior.

##########
File path: pulsar-broker/src/main/java/org/apache/pulsar/broker/delayed/InMemoryDelayedDeliveryTracker.java
##########
@@ -78,6 +83,17 @@ public boolean addMessage(long ledgerId, long entryId, long deliveryAt) {
             return false;
         }
 
+        synchronized (this) {

Review comment:
       I think we don't need `synchronized` here?
   
   The `InMemoryDelayedDeliveryTracker` is not a thread-safe container.

##########
File path: pulsar-broker/src/main/java/org/apache/pulsar/broker/delayed/InMemoryDelayedDeliveryTracker.java
##########
@@ -78,6 +83,17 @@ public boolean addMessage(long ledgerId, long entryId, long deliveryAt) {
             return false;
         }
 
+        synchronized (this) {
+            if (ComparisonChain.start().compare(ledgerId, lastLedgerId).compare(entryId, lastEntryId).result() <= 0) {

Review comment:
       Using Guava's ComparisonChain will create object instances.
   
   ```java
   if (ledgerId < lastLedgerId || (ledgerId == lastLedgerId && entryId < lastEntryId))
   ```




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