KAFKA-16709: add comments to explain the possible race condition

apache · May 23, 2024 · 0d78e49 · 0d78e49
1 parent 4a1b76d
commit 0d78e49
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/core/src/main/scala/kafka/server/ReplicaManager.scala b/core/src/main/scala/kafka/server/ReplicaManager.scala
@@ -2127,8 +2127,11 @@ class ReplicaManager(val config: KafkaConfig,
       }
     }
 
-    if (futureReplicasAndInitialOffset.nonEmpty)
+    if (futureReplicasAndInitialOffset.nonEmpty) {
+      // Even though it's possible that there is another thread adding fetcher for this future log partition,
+      // but it's fine because `BrokerIdAndFetcherId` will be identical the operation will be no-op.
       replicaAlterLogDirsManager.addFetcherForPartitions(futureReplicasAndInitialOffset)
+    }
   }
 
   /*