mjsax commented on code in PR #21642:
URL: https://github.com/apache/kafka/pull/21642#discussion_r2897935030


##########
streams/integration-tests/src/test/java/org/apache/kafka/streams/integration/RebalanceProtocolMigrationIntegrationTest.java:
##########
@@ -134,6 +145,125 @@ public void 
shouldMigrateToAndFromStreamsRebalanceProtocol() throws Exception {
         processExactlyOneRecord(streamsBuilder, props, "3", "C");
     }
 
+    @Test
+    public void shouldMigrateFromClassicToStreamsAfterBrokerRestart() throws 
Exception {
+        // This test reproduces KAFKA-20254: after log compaction removes the
+        // GroupMetadata tombstone from __consumer_offsets, offset commit 
records
+        // (which precede the streams group records in the log) create a simple
+        // classic group during replay, and then the streams group records must
+        // handle this existing simple classic group.
+        final StreamsBuilder streamsBuilder = new StreamsBuilder();
+        final KStream<String, String> input = streamsBuilder.stream(
+            inputTopic, Consumed.with(Serdes.String(), Serdes.String()));
+        input.to(outputTopic, Produced.with(Serdes.String(), Serdes.String()));
+
+        final Properties props = props();
+        final String appId = 
props.getProperty(StreamsConfig.APPLICATION_ID_CONFIG);
+
+        // Step 1: Run with the classic protocol and process a record.
+        props.put(StreamsConfig.GROUP_PROTOCOL_CONFIG, 
GroupProtocol.CLASSIC.name());
+        processExactlyOneRecord(streamsBuilder, props, "1", "A");
+
+        // Wait for session to time out so the group becomes empty.
+        try (final Admin adminClient = 
Admin.create(Map.of(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, 
CLUSTER.bootstrapServers()))) {
+            waitForEmptyConsumerGroup(adminClient, appId, 1000);
+        }
+
+        // Step 2: Commit an offset for an "orphan" topic using the same group 
ID.
+        // This offset commit record will precede the streams group records in 
the
+        // log and will survive compaction because the streams group never 
commits
+        // for this topic-partition.
+        final String orphanTopic = "orphan-" + safeTestName;
+        CLUSTER.createTopic(orphanTopic);
+        commitOrphanOffset(appId, orphanTopic);
+
+        // Step 3: Migrate to the streams protocol and process a record. This
+        // writes a GroupMetadata tombstone for the classic group followed by
+        // streams group records.
+        props.put(StreamsConfig.GROUP_PROTOCOL_CONFIG, 
GroupProtocol.STREAMS.name());
+        processExactlyOneRecord(streamsBuilder, props, "2", "B");
+
+        // Step 4: Configure aggressive compaction so that the GroupMetadata
+        // tombstone is removed, leaving only the orphan offset commit record
+        // before the streams group records.
+        configureAggressiveCompaction();
+
+        // Step 5: Flood __consumer_offsets with offset commits to trigger 
segment
+        // rotation and compaction.
+        floodConsumerOffsetsForCompaction();
+
+        // Wait for compaction to clean up the GroupMetadata tombstone.
+        Thread.sleep(5000);

Review Comment:
   The newly added `rollAndCompactConsumerOffsets` doesn't do the trick?



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]

Reply via email to