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From Robert Coli <rc...@eventbrite.com>
Subject Re: Deletes Reappeared even when nodes are not down
Date Fri, 13 Nov 2015 22:57:32 GMT
On Fri, Nov 13, 2015 at 1:47 PM, Peddi, Praveen <peddi@amazon.com> wrote:

> We do not currently run repairs because we know our deployment time for
> each cassandra node is very short. I do understand we have to run repairs
> but would repair be in the picture here when no nodes in the cluster were
> down for last 2 weeks?
>

The only mechanism Cassandra provides that *ensures* that data doesn't
undelete itself after gc_grace_seconds is periodic repair.

To expand slightly on what rustyrazorblade says down-thread, you might have
:

1) dropped a mutation
2) stored a hint
3) failed to deliver that hint

If that hint was a DELETE, you will unmask the deleted data once
gc_grace_seconds has passed and the tombstone has been compacted away on
other nodes.

=Rob

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