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From Robert Coli <>
Subject Re: Questions about cleaning up/purging Hinted Handoffs
Date Fri, 05 Sep 2014 17:03:32 GMT
On Fri, Sep 5, 2014 at 6:12 AM, Rahul Neelakantan <> wrote:

> The questions are for Cassandra 1.0.8 but may apply to later versions too.

Upgrade your very old version of Cassandra ASAP. I barely remember the
implementation of HH in your old version.

> 1) When the coordinator notices that a node it is collecting hints for is
> down for more than the max hint window, it stops collecting hints for that
> node
>     - Does it automatically purge the hints it collected so far, or does
> removing them require manual intervention?

It tries to deliver the hints it has stored so far, when it can. When it
delivers them, it deletes them.

>     - What is the recommended way to remove hints if they are not
> automatically removed? Stop node and delete hints CF db files? or use
> truncate CF?

Either way is fine. There's also a JMX method (maybe not in your old
version) to purge hints.

> 2) When the coordinator replays hints to a node that has come back within
> the max hint window, does it purge those hints once they are replayed or
> does cleanup of those hints require manual intervention?

The former.

> 3) If a node is flapping because of network issues and gossip keeps
> thinking the node is down, causing the coordinator to reset the max hint
> window for that node and start collecting hints again for the node
>  - Does it automatically purge the hints collected in the previous windows?


>  - Or Does it replay all hints collected in all windows that the node was
> down?



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