Github user srdo commented on the issue:
https://github.com/apache/storm/pull/2307
@HeartSaVioR Yes, you are right. We set the auto offset reset policy to
`earliest` by default when `AT_LEAST_ONCE` is picked if the user hasn't
explicitly set anything else.
The misconfiguration I'm most worried about is where users set
`AT_LEAST_ONCE`, and then forget to set the auto offset reset policy which
defaults to `latest`, because it's an easy mistake to make if you're not
already very familiar with Kafka's options. The other weird configurations
(`AT_LEAST_ONCE`+`latest`, `AT_MOST_ONCE`+`earliest`) have to be explicitly
chosen by the user.
I can't think of a reason why users would want to use those configurations,
but I thought it might be better not to prevent the user from using those
settings if they really want to, because there might be a use case I'm not
seeing.
I'm happy to add in checks and error messages (or maybe even throwing
exceptions) when using those configurations, if you think it makes sense?
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