I used to present Cassandra as a NoSQL datastore with "distributed" table.
This definition is closer to CQL and has some academic background
(distributed hash table).


On Fri, Sep 30, 2016 at 7:43 PM, Benedict Elliott Smith <bened...@apache.org
> wrote:

> Cassandra is not a "wide column store" anymore.  It has a schema.  Only
> thrift users no longer think they have a schema (though they do), and
> thrift is being deprecated.
>
> I really wish everyone would kill the term "wide column store" with fire.
> It seems to have never meant anything beyond "schema-less, row-oriented",
> and a "column store" means literally the opposite of this.
>
> Not only that, but people don't even seem to realise the term "column
> store" existed long before "wide column store" and the latter is often
> abbreviated to the former, as here: http://www.planetcassandra.
> org/what-is-nosql/
>
> Since it no longer applies, let's all agree as a community to forget this
> awful nomenclature ever existed.
>
>
>
> On 30 September 2016 at 18:09, Joaquin Casares <joaq...@thelastpickle.com>
> wrote:
>
>> Hi Mehdi,
>>
>> I can help clarify a few things.
>>
>> As Carlos said, Cassandra is a Wide Column Store. Theoretically a row can
>> have 2 billion columns, but in practice it shouldn't have more than 100
>> million columns.
>>
>> Cassandra partitions data to certain nodes based on the partition key(s),
>> but does provide the option of setting zero or more clustering keys.
>> Together, the partition key(s) and clustering key(s) form the primary key.
>>
>> When writing to Cassandra, you will need to provide the full primary key,
>> however, when reading from Cassandra, you only need to provide the full
>> partition key.
>>
>> When you only provide the partition key for a read operation, you're able
>> to return all columns that exist on that partition with low latency. These
>> columns are displayed as "CQL rows" to make it easier to reason about.
>>
>> Consider the schema:
>>
>> CREATE TABLE foo (
>>   bar uuid,
>>
>>   boz uuid,
>>
>>   baz timeuuid,
>>   data1 text,
>>
>>   data2 text,
>>
>>   PRIMARY KEY ((bar, boz), baz)
>>
>> );
>>
>>
>> When you write to Cassandra you will need to send bar, boz, and baz and
>> optionally data*, if it's relevant for that CQL row. If you chose not to
>> define a data* field for a particular CQL row, then nothing is stored nor
>> allocated on disk. But I wouldn't consider that caveat to be "schema-less".
>>
>> However, all writes to the same bar/boz will end up on the same Cassandra
>> replica set (a configurable number of nodes) and be stored on the same
>> place(s) on disk within the SSTable(s). And on disk, each field that's not
>> a partition key is stored as a column, including clustering keys (this is
>> optimized in Cassandra 3+, but now we're getting deep into internals).
>>
>> In this way you can get fast responses for all activity for bar/boz
>> either over time, or for a specific time, with roughly the same number of
>> disk seeks, with varying lengths on the disk scans.
>>
>> Hope that helps!
>>
>> Joaquin Casares
>> Consultant
>> Austin, TX
>>
>> Apache Cassandra Consulting
>> http://www.thelastpickle.com
>>
>> On Fri, Sep 30, 2016 at 11:40 AM, Carlos Alonso <i...@mrcalonso.com>
>> wrote:
>>
>>> Cassandra is a Wide Column Store http://db-engines.com/en
>>> /system/Cassandra
>>>
>>> Carlos Alonso | Software Engineer | @calonso
>>> <https://twitter.com/calonso>
>>>
>>> On 30 September 2016 at 18:24, Mehdi Bada <mehdi.b...@dbi-services.com>
>>> wrote:
>>>
>>>> Hi all,
>>>>
>>>> I have a theoritical question:
>>>> - Is Apache Cassandra really a column store?
>>>> Column store mean storing the data as column rather than as a rows.
>>>>
>>>> In fact C* store the data as row, and data is partionned with row key.
>>>>
>>>> Finally, for me, Cassandra is a row oriented schema less DBMS.... Is it
>>>> true for you also???
>>>>
>>>> Many thanks in advance for your reply
>>>>
>>>> Best Regards
>>>> Mehdi Bada
>>>> ----
>>>>
>>>> *Mehdi Bada* | Consultant
>>>> Phone: +41 32 422 96 00 | Mobile: +41 79 928 75 48 | Fax: +41 32 422
>>>> 96 15
>>>> dbi services, Rue de la Jeunesse 2, CH-2800 Delémont
>>>> mehdi.b...@dbi-services.com
>>>> www.dbi-services.com
>>>>
>>>>
>>>>
>>>>
>>>> *⇒ dbi services is recruiting Oracle & SQL Server experts ! – Join the
>>>> team
>>>> <http://www.dbi-services.com/fr/dbi-services-et-ses-collaborateurs/offres-emplois-opportunites-carrieres/>*
>>>>
>>>
>>>
>>
>

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