Github user miguno commented on the pull request:
https://github.com/apache/storm/pull/429#issuecomment-74147926
If you need at-least-once processing you must use an acking topology, which
will allow Storm to replay lost messages. If instead you go with an unacking
topology (= no guaranteed message processing) then you may run into data loss.
There re pros and cons for each variant, and e.g. in our case we use both
depending on the use case.
Also: The semantics described above have been in Storm right from the
beginning. None of these have been changed by this pull request.
> On 12.02.2015, at 20:01, Daniel Schonfeld <notificati...@github.com>
wrote:
>
> Doesn't dropping the messages coming from a non ack/fail caring spout
negate the 'at least once' attempt of storm? I mean doesn't that kinda force
you to make all your spouts ack/fail aware where before you could have gotten
away without it?
>
> In other words. There is a chance that if the worker that died is the one
containing the spout and if the first bolt is located on another worker, that
technically at-least once wasn't tried but rather fell to the floor right away.
>
> â
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