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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Consistency Level of CLI
Date Thu, 25 Feb 2010 19:12:38 GMT
CLI uses CL.ONE for reads and writes.

It has no user-level documentation other than its help output.

On Thu, Feb 25, 2010 at 1:08 PM, Masood Mortazavi <masoodmortazavi@gmail.com
> wrote:

>
>
> What is the write and read consistency level for the CLI tool
> "cassandra-cli" ?
>
> Do the "set" and "get" commands in the "cli" allow the Consistency Level to
> be specified for a given "set" or "get"?
>
> Is there a current specification of CLI anywhere on the wiki?
>
> ( How are JIRA's related to the CLI tagged in the JIRA system assuming they
> are "tagged" separately? In other words, is there an identifier for them? )
>
> Regards,
> m.
>
> ==========================
> The Cassandra "API" describes write and read consistency levels as follows:
> http://wiki.apache.org/cassandra/API
> Write
>
> *Level*
>
> *Behavior*
>
> ZERO
>
> Ensure nothing. A write happens asynchronously in background
>
> ANY
>
> (Coming in 0.6) Ensure that the write has been written to at least 1 node,
> including hinted recipients.
>
> ONE
>
> Ensure that the write has been written to at least 1 node's commit log and
> memory table before responding to the client.
>
> QUORUM
>
> Ensure that the write has been written to <ReplicationFactor> / 2 + 1nodes before
responding to the client.
>
> ALL
>
> Ensure that the write is written to all <ReplicationFactor> nodes before
> responding to the client. Any unresponsive nodes will fail the operation.
>
> Read
>
> *Level*
>
> *Behavior*
>
> ZERO
>
> Not supported, because it doesn't make sense.
>
> ANY
>
> Not supported. You probably want ONE instead.
>
> ONE
>
> Will return the record returned by the first node to respond. A consistency
> check is always done in a background thread to fix any consistency issues
> when ConsistencyLevel.ONE is used. This means subsequent calls will have
> correct data even if the initial read gets an older value. (This is called
> read repair.)
>
> QUORUM
>
> Will query all storage nodes and return the record with the most recent
> timestamp once it has at least a majority of replicas reported. Again, the
> remaining replicas will be checked in the background.
>
> ALL
>
> Will query all storage nodes and return the record with the most recent
> timestamp once all nodes have replied. Any unresponsive nodes will fail the
> operatio
>
>

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