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From: "Till Westmann" <tillw@apache.org>
To: dev@asterixdb.apache.org
Subject: Re: Force LSM component flush & NC-CC messaging ACK
Date: Sat, 21 Jan 2017 15:21:39 +0100
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archived-at: Sat, 21 Jan 2017 14:21:50 -0000

Hi Ildar,

On 19 Jan 2017, at 4:02, Ildar Absalyamov wrote:

> Since I was out for quite a while and a lot of things happened in a 
> meantime in a codebase I wanted to clarify couple of things.
>
> I was wondering if there is any legitimate way to force the data of 
> in-memory components to be flushed, other then stop the whole 
> instance?
> It used to be that choosing a different default dataverse with 
> “use” statement did that trick, but that is not the case anymore.

Just wondering, why do you want to flush the in-memory components to 
disk?

> Another question is regarding CC<->NC & NC<->NC messaging. Does the 
> sender get some kind of ACK that the message was received by the 
> addressee? Say if I send a message just before the instance shutdown 
> will the shutdown hook wait until the message is delivered and 
> processed?

I agree with Murtadha, that I can certainly be done. However, we also 
need to assume that some shutdowns won’t be clean and so the messages 
might not be received. So it might be easier to just be able to recover 
from missing messages than to be able to recover *and* to synchronize on 
shutdown. Just a thought - maybe that’s not even an issue for your 
use-case.

Cheers,
Till