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Re: Is there any chance the bootstrapping lost data?




> On Dec 28, 2018, at 2:17 AM, Jinhua Luo <luajit.io@xxxxxxxxx> wrote:
> 
> Hi All,
> 
> While the pending node get streaming of token ranges from other nodes,
> all coordinator would send new writes to it so that it would not miss
> any new data, correct?
> 
> I have two (maybe silly) questions here:
> Given the CL is ONE,
> a) what if the coordinator haven't meet the pending node via gossip,
> and only sends mutation to the main replica (the replica would be
> replaced by the pending node)?

There’s a delay between joining in gossip and calculating the bootstrap streaming plan to mitigate this 

There’s also protections added in recent versions to avoid ack’ing a write (or read or stream) for ranges that don’t properly own the range, so topology/gossip disagreements shouldn’t result in consistency violations. 

> b) what if the coordinator fails to send the mutation to pending node?

The coordinators increase consistency level/ blockFor by one for each pending node, so the pending node may not get the write if your RF is > 1, but enough nodes will that you’ll meet your consistency guarantee

> 
> In both cases, when the pending node finish streaming and join the
> ring eventually, the mutation mentioned above would be lost?
> 
> Regards,
> Jinhua Luo
> 
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