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@@ -224,3 +224,27 @@ to partitions.
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- If a new partition becomes available, or a consumer fails, or is added,
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the Group Coordinator initiates the rebalancing protocol, engaging each Consumer coordinator
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+## Consumer configuration: performance and efficiency
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+
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+- `fetch.min.bytes` : minimum number of bytes returned from the poll. Analogous
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+ to the `batch.size` settings on the producer
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+- `max.fetch.wait.ms` maximum time to wait if that threshold has not yet been met.
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+ Analogous to the `linger.ms` setting on the producer
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+- `max.partition.fetch.bytes`: maximum number of bytes per partition returned in a
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+ `poll()` call, to avoid spending too much time on processing before calling
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+ `poll()` again.
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+- `max.poll.records` similar but in terms of records, not bytes, and not per partition
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+
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+## Advanced topics not covered
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+
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+- Consumer position control
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+ - `seek(TopicPartition, long)`: specify the offset from which to read on a
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+ given partition
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+ - `seekToBeginning(Collection<TopicPartition>)`: seek from the beginning of a group of topics and partitions
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+ - `seekToEnd(Collection<TopicPartition>)`: its opposite
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+- Flow control allows pausing/resuming subscription to some topics or partitions
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+ - `pause(TopicPartition)`
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+ - `resume(TopicPartition)`
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+ - mostly useful when a single consumer has to read multiple topics and partitions
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+- Rebalance listeners: get notified when rebalances occur in the cluster, to adjust
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+ in consumer code how to handle the offsets.
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