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From graham sanderson <gra...@vast.com>
Subject A few questions from a new user
Date Sat, 07 Jul 2012 17:18:08 GMT
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.


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