How to update a message using ExcerptTailer?

[Mickael Marrache]

Hi,

I often read that ExcerptTailer can be used to update a message in a queue but I can't find any relevant method.

Should an appender be used instead?

Thanks,

Mickael

[Peter Lawrey]

Hi,

You can update a message via a Tailer writing to the underlying wire.bytes(), or reading using bound values i.e. values that when you update them, you alter the original record.

Regards,

    Peter.

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[Mickael Marrache]

My goal is to keep an output queue that will always include one value which represents the index of the last successfully processed message.

Therefore, instead of appending indexes, I prefer to update it so that my output queue never grows.

I looked for something related to bound values in the ExcerptTailer interface, but can't see anything relevant...

[Peter Lawrey]

While you can do as you suggest, the pattern to use is storing the result of each message in an output queue and replaying from there.

https://vanilla-java.github.io/2016/03/29/Microservices-in-the-Chronicle-world-Part-4.html

Note: if you roll the files often, the value you want to store will also be rolled.

You can instead mark each message as processed.