I was being a little tongue in cheek! On Jul 23, 2014, at 3:20 PM, Jack Krupansky <j...@basetechnology.com> wrote:
> Granted, for “normal” apps it is unlikely to be appropriate but... > > From an old post by Jonathan: > --- > Extreme write availability > > For applications that want Cassandra to accept writes even when all the > normal replicas are down (so even ConsistencyLevel.ONE cannot be satisfied), > Cassandra provides ConsistencyLevel.ANY. ConsistencyLevel.ANY guarantees that > the write is durable and will be readable once an appropriate replica target > becomes available and receives the hint replay. > --- > See: > http://www.datastax.com/dev/blog/understanding-hinted-handoff > > I can think of a couple of use cases: sensor data where the devices are > streaming frequently, so losing a reading is not a big deal because another > reading is coming soon anyway, and a Twitter firehose where you are after a > robust sample rather than absolute consistency. Minimizing network latency > may be a bigger deal than whether immediate queries can see the data. > > And as the description notes, hinted handoff will eventually propagate the > data (unless it times out and drops the hint.) > > -- Jack Krupansky > > From: Robert Coli > Sent: Wednesday, July 23, 2014 1:15 PM > To: user@cassandra.apache.org > Cc: Kevin Burton > Subject: Re: All writes fail with ONE consistency level when adding second > node to cluster? > > On Tue, Jul 22, 2014 at 7:46 PM, Andrew <redmu...@gmail.com> wrote: > > ONE means write to one replica (in addition to the original). If you want to > write to any of them, use ANY. Is that the right understanding? > > > This has come up a few times, so let me be unambiguous about when to use > CL.ANY : > > NEVER EVER USE CL.ANY. IT ALMOST CERTAINLY SHOULD NOT EVEN EXIST. > > IF YOU THINK YOU NEED TO USE IT, YOU ARE ALMOST CERTAINLY WRONG. > > ;D > > =Rob >
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