Fence writer zombies (breaking change) #255
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| send(events, offsets, new ConsumerGroupMetadata(config.controlGroupId())); | ||
| send(ImmutableList.of(), offsets, new ConsumerGroupMetadata(config.connectGroupId())); | ||
| send(events, offsets, consumerGroupMetadata); |
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Notice how we commit offsets against only one consumer group now; the connect-<connector-name> consumer group.
We no longer commit source topic offsets to the config.controlGroupId and TBH I don't understand why we ever did since we could have always taken this approach (irrespective of zombie fencing) cc @bryanck if you can shed any light here as to why this was necessary in the past or if it was just an oversight.
| try { | ||
| groupMetadata = KafkaUtils.consumerGroupMetadata(context); | ||
| } catch (IllegalArgumentException e) { | ||
| LOG.warn("Could not extract ConsumerGroupMetadata from consumer inside Kafka Connect, falling back to simple ConsumerGroupMetadata which can result in duplicates from zombie tasks"); | ||
| groupMetadata = new ConsumerGroupMetadata(config.connectGroupId()); | ||
| } |
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We fetch the consumer-group-metadata via reflection from inside the Kafka Connect framework. This is technically unsafe as we are relying on private, implementation details. Hence I also implemented falling back to simple ConsumerGroupMetadata (which is basically what we were doing previously) and does not do zombie fencing.
| private static final String WorkerSinkTaskContextClassName = | ||
| WorkerSinkTaskContext.class.getName(); | ||
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| @SuppressWarnings("unchecked") |
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worth a comment around using reflection to get at some very specific implementation detail stuff here but otherwise 👍
| @@ -170,6 +172,105 @@ from the classpath are loaded. Next, if `iceberg.hadoop-conf-dir` is specified, | |||
| are loaded from that location. Finally, any `iceberg.hadoop.*` properties from the sink config are | |||
| applied. When merging these, the order of precedence is sink config > config dir > classpath. | |||
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| # Upgrade | |||
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Nice docs. Thanks for looking out for the users.
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Out of scope for this PR: Coordinator zombie fencing