This is theory but not the all practice. The failure detector heartbeats is
a process happening outside the read.
Take for example a cluster with Replication Factor 3.
At time('1) the failure detector might read three nodes as UP.
A request "soon after '1" issued at time(`2) might start a read process.
One of the three nodes may not respond within the read timeout window.Call
the end of the read timeout window time('3)
Note: Anti-entropy read-repair like Read repair is set to only happen a
fraction of requests.
Note: Anti-entropy read-repair is (async) not guaranteed not retried (might
need a fact check but fairly sure of this)
A read-repair may be issue at time('4) moments after time('3).
Those read repairs could fail or pass as well.
The long and short is well the day may be repaired after a read of ALL.
There is no guarantee that it will be.
.
On Tue, Oct 11, 2016 at 1:29 PM, Jeff Jirsa <jeff.ji...@crowdstrike.com>
wrote:
> If the failuredetector knows that the node is down, it won’t attempt a
> read, because the consistency level can’t be satisfied – none of the other
> replicas will be repaired.
>
>
>
>
>
> *From: *Anubhav Kale <anubhav.k...@microsoft.com>
> *Reply-To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
> *Date: *Tuesday, October 11, 2016 at 10:24 AM
> *To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
> *Subject: *Question on Read Repair
>
>
>
> Hello,
>
>
>
> This is more of a theory / concept question. I set CL=ALL and do a read.
> Say one replica was down, will the rest of the replicas get repaired as
> part of this ? (I am hoping the answer is yes).
>
>
>
> Thanks !
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