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Kafka >> mail # user >> A few questions from a new user


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A few questions from a new user
1) I would like to guarantee that a group of messages are always delivered in their entirety together (because there is contextual information in messages which precede other messages). I'm a little confused by the use of the term "nested message sets" since I don't really see much in the code (though II don't really know Scala) - perhaps this refers to the fact that you can have a set of messages within a message set file on disk. Anyway, I was curious (and I'm using the Java api now, but may move to the Scala later) what I need to do to guarantee N messages are sent and delivered as a single message set; is a single ProducerData with a List of messages always sent as a single message set? does compression need to be turned on? how does this affect network limits etc. (i.e. does the entire message set have to fit). I'm also assuming that once I have my message set containing all my messages it will be discarded in its entirety.

2) Related to 1) from the consumer side, can I tell the boundaries of a message set (perhaps not required for me), but nevertheless I do want to make sure I receive the entire set in one go (again do I have to set network limits accordingly). The docs say that the entire message set is always delivered to the client when compressed, but I'm not sure if it can be subdivided if not compressed. Note I'm happy to stick with compression if required.

3) So I'm using the ZookeeperConsumerConnector, since I don't want to manage finding the brokers myself, however I was wondering if there are any plans to decouple the consumer offset tracking from the former. One of my use cases is that I'll have a lot of ad-hoc one off consumers that simply read a subset of data until they die - from looking at ConsoleConsumer, there is currently a hack to simply delete the zookeeper info after the fact to get around this.

Thanks,

Graham.
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Niek Sanders 2012-07-07, 20:30
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Graham Sanderson 2012-07-07, 23:37
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Jay Kreps 2012-07-09, 16:13
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graham sanderson 2012-07-09, 17:51