[GitHub] [kafka] lbradstreet commented on a change in pull request #7222: KAFKA-8806 Reduce calls to validateOffsetsIfNeeded

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

lbradstreet commented on a change in pull request #7222:
URL: https://github.com/apache/kafka/pull/7222#discussion_r467187874



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File path: clients/src/main/java/org/apache/kafka/clients/consumer/internals/SubscriptionState.java
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@@ -422,10 +421,13 @@ synchronized int numAssignedPartitions() {
     }
 
     synchronized List<TopicPartition> fetchablePartitions(Predicate<TopicPartition> isAvailable) {
-        return assignment.stream()
-                .filter(tpState -> isAvailable.test(tpState.topicPartition()) && tpState.value().isFetchable())
-                .map(PartitionStates.PartitionState::topicPartition)
-                .collect(Collectors.toList());
+        List<TopicPartition> result = new ArrayList<>();

Review comment:
       We should add a small comment that this is in the hotpath and is written the "ugly" way for a reason. It's also probably worth mentioning that we do the cheap isFetchable check first.




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