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https://issues.apache.org/jira/browse/KAFKA-10576?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17211577#comment-17211577
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huxihx commented on KAFKA-10576:
--------------------------------
`commitAsync` does need subsequent `poll` calls to take effect, so I prefer
option #2 here.
> Different behavior of commitSync and commitAsync
> ------------------------------------------------
>
> Key: KAFKA-10576
> URL: https://issues.apache.org/jira/browse/KAFKA-10576
> Project: Kafka
> Issue Type: Bug
> Components: consumer
> Reporter: Yuriy Badalyantc
> Priority: Major
>
> It looks like {{commitSync}} and {{commitAsync}} consumer's methods have a
> different semantic.
> {code:java}
> public class TestKafka {
> public static void main(String[]args) {
> String id = "dev_test";
> Map<String, Object> settings = new HashMap<>();
> settings.put("bootstrap.servers", "localhost:9094");
> settings.put("key.deserializer", StringDeserializer.class);
> settings.put("value.deserializer", StringDeserializer.class);
> settings.put("client.id", id);
> settings.put("group.id", id);
> String topic = "test";
> Map<TopicPartition, OffsetAndMetadata> offsets = new HashMap<>();
> offsets.put(new TopicPartition(topic, 0), new OffsetAndMetadata(1));
> try (KafkaConsumer<String, String> consumer = new
> KafkaConsumer<>(settings)) {
> consumer.commitSync(offsets);
> }
> }
> }
> {code}
> In the example above I created a consumer and use {{commitSync}} to commit
> offsets. This code works as expected — all offsets are committed to kafka.
> But in the case of {{commitAsync}} it will not work:
> {code:java}
> try (KafkaConsumer<String, String> consumer = new KafkaConsumer<>(settings)) {
> CompletableFuture<Boolean> result = new CompletableFuture<>();
> consumer.commitAsync(offsets, new OffsetCommitCallback() {
> @Override
> public void onComplete(Map<TopicPartition, OffsetAndMetadata>
> offsets, Exception exception) {
> if (exception != null) {
> result.completeExceptionally(exception);
> } else {
> result.complete(true);
> }
> }
> });
> result.get(15L, TimeUnit.SECONDS);
> }
> {code}
> The {{result}} future failed with a timeout.
> This behavior is pretty surprising. From naming and documentation, it looks
> like {{commitSync}} and {{commitAsync}} methods should behave identically. Of
> course, besides the blocking/non-blocking aspect. But in reality, there are
> some differences.
> I can assume that the {{commitAsync}} method somehow depends on the {{poll}}
> calls. But I didn't find any explicit information about it in
> {{KafkaConsumer}}'s javadoc or kafka documentation page.
> So, I believe that there are the next options:
> # It's a bug and not expected behavior. {{commitSync}} and {{commitAsync}}
> should have identical semantics.
> # It's expected, but not well-documented behavior. In that case, this
> behavior should be explicitly documented.
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