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https://issues.apache.org/jira/browse/KAFKA-13985?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chris Egerton updated KAFKA-13985:
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Fix Version/s: 3.4.0
> MirrorSourceTask commitRecord throws NPE if SMT is filtering out source record
> ------------------------------------------------------------------------------
>
> Key: KAFKA-13985
> URL: https://issues.apache.org/jira/browse/KAFKA-13985
> Project: Kafka
> Issue Type: Bug
> Components: mirrormaker
> Affects Versions: 3.1.0, 3.2.0
> Reporter: Jacopo Riciputi
> Assignee: Rens Groothuijsen
> Priority: Minor
> Fix For: 3.4.0
>
>
> Applying a SMT that filters out messages it can brings to enter in this path:
> From WorkerSourceTask.java
> {code:java}
> final SourceRecord record = transformationChain.apply(preTransformRecord);
> final ProducerRecord<byte[], byte[]> producerRecord =
> convertTransformedRecord(record);
> if (producerRecord == null || retryWithToleranceOperator.failed()) {
> counter.skipRecord();
> commitTaskRecord(preTransformRecord, null);
> continue;
> } {code}
>
> Then to:
> {code:java}
> private void commitTaskRecord(SourceRecord record, RecordMetadata metadata) {
> try {
> task.commitRecord(record, metadata);
> } catch (Throwable t) {
> log.error("{} Exception thrown while calling
> task.commitRecord()", this, t);
> }
> }{code}
> Finally
> From MirrorSourceTask.java
> {code:java}
> @Override
> public void commitRecord(SourceRecord record, RecordMetadata metadata) {
> try {
> if (stopping) {
> return;
> }
> if (!metadata.hasOffset()) {
> log.error("RecordMetadata has no offset -- can't sync offsets
> for {}.", record.topic());
> return;
> }
> ...{code}
>
> Causing a NPE because metadata is null.
> This the exception.
> {code:java}
> [2022-06-13 12:31:33,094] WARN Failure committing record.
> (org.apache.kafka.connect.mirror.MirrorSourceTask:190)
> java.lang.NullPointerException
> at
> org.apache.kafka.connect.mirror.MirrorSourceTask.commitRecord(MirrorSourceTask.java:177)
> at
> org.apache.kafka.connect.runtime.WorkerSourceTask.commitTaskRecord(WorkerSourceTask.java:463)
> at
> org.apache.kafka.connect.runtime.WorkerSourceTask.sendRecords(WorkerSourceTask.java:358)
> at
> org.apache.kafka.connect.runtime.WorkerSourceTask.execute(WorkerSourceTask.java:257)
> at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:188)
> at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:243)
> at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown
> Source)
> at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
> at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown
> Source)
> at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown
> Source)
> at java.base/java.lang.Thread.run(Unknown Source) {code}
> In my understanding this is well handled and it does not have negative
> impacts because it's handled by MirrorSourceTask.commitRecord, without
> leaving the exception be forwarded outside of it.
> But probably is preferred to handle it checking if metadata != null.
> So skipping commit but safely and silently
> [EDIT]
> Actually, going a bit in deep, there is a small side-effect.
> If the latest message elaborated was filtered out (so not committed by
> MirrorSourceTask), if MM2 instance is rebooted, this message will be re-read
> by consumer, because offset was not committed (and probably filtered out if
> configurations wasn't change).
> But probably this behavior is fine considering MM2's nature
>
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