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From aaron morton <aa...@thelastpickle.com>
Subject Re: CQL How to do
Date Mon, 06 Jun 2011 00:01:58 GMT
From what I've seen of CQL there is no comparison between the potential complexity of a CQL
statement and that of a SQL statement. IMHO CQL is more or less a human readable form of the
current API, it does not add features. SQL statements are arbitrarily complex and may generate
many possible query plans which need to be somehow compared and optimised. 
 
I'll add another pro to using CQL, it will be a lot easier for people to describe a query
they have sent to the server. It will make the helping people using multiple languages a bit
easier if they can grab a log record and post the query they sent.

I'm keen to see how it goes.    

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 6 Jun 2011, at 03:27, Eric Evans wrote:

> On Sun, 2011-06-05 at 00:51 -0400, Jeffrey Kesselman wrote:
>> Is CQL really the path for the future for Cassandra?
> 
> CQL is no more or less "official" than the Thrift interface, and TTBMK,
> there is no secret cabal that met to decide it would be The Way.  People
> will use what works best for them, and if a de facto standard emerges
> (it usually does), then so much the better.
> 
>> It seems to me by introducing a textual language that has to be parsed
>> and understood, you are adding back in some of the inefficiency of
>> SQl...
> 
> I think this "inefficiency" remains to be proven.  Or if it is less
> inefficient, if it is enough so to warrant a discussion.
> 
> No matter what the technology, you have to have a client send a query to
> the server structured in some way.  Once received, the server has to
> "parse" that structure before it can act.  What is different, is that
> CQL structures the query in a human-readable string, and Thrift
> structures it as a hierarchy of records serialized to binary.
> 
> It may be true that CQL parsing has higher overhead (Thrift does more
> object creation and is likely worse on gc), but Cassandra nodes are
> typically limited by disk IO and have loads of idle processor time.  I
> might be biased, but I think it is easy to justify considering how much
> easier CQL makes things.
> 
>> 2011/6/4 aaron morton <aaron@thelastpickle.com>:
>>> May be wrong but as far as I know thrift is still the official API, for now.
>>> CQL is in it's first release and still has a few things to be added to
>>> it https://issues.apache.org/jira/browse/CASSANDRA-2472 . That said, jump in
>>> and try it out :)
>>> The best documentation I can point you to is
>>> https://github.com/apache/cassandra/blob/cassandra-0.8.0/doc/cql/CQL.textile
>>> There are Java,  Python and Twisted Python drivers in the source tree under
>>> the drivers/ directory.
>>> Hope that helps.
>>> -----------------
>>> Aaron Morton
>>> Freelance Cassandra Developer
>>> @aaronmorton
>>> http://www.thelastpickle.com
>>> On 5 Jun 2011, at 04:16, Yonder wrote:
>>> 
>>> Hi,
>>> 
>>> In Cassandra 0.8, CQL become the primary client interface, but I don't know
>>> how to use it in a non-command line env. I could not find out any how-to do
>>> docs in Wiki or DataStax's website.
> 
> -- 
> Eric Evans
> eevans@rackspace.com
> 


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