Is the batch wise processing implemented or is all the data fetched still?

On Fri, Aug 24, 2012 at 6:20 PM, Anjana Fernando <[email protected]> wrote:

> Hi,
>
> IMO, we just should not be doing the counting of the records. So
> basically, you will not get the record count by default. But we can add it
> as an option for the Cassandra explorer, to get the whole row count of a CF
> when the user request it, i.e. pressing a button. So with this, pagination
> will not be supported by default, and just give the user to advance a batch
> of records with a "next" button. And also, it would be great, if we can
> integrate CQL support for the explorer, so the user can filter the data in
> a specific way and get the resultant records.
>
> Cheers,
> Anjana.
>
> On Fri, Aug 24, 2012 at 6:01 PM, Shelan Perera <[email protected]> wrote:
>
>> Hi,
>>
>>  Cassandra Explorer has been testing with 7 million row entries with BAM
>> data and it gives timeout errors with such a load. The main reason for this
>> is calculating the total no of rows
>> to show how many row entries are available and to enable full numbered
>> pagination. In Cassandra calculating total no of Rows is an anti pattern
>> but that is the key information which is used
>> heavily to verify inserted data by application. Almost all the available
>> tools are using a limit such as 10000 rows as the limit and not going for
>> total records.
>>
>> I have tried fetching records as batches (10000 each and 100,000 each on
>> different occasions) but to complete a limit like 7 million it takes a
>> considerable time. When i googled they have advised it is not a good
>> idea to calculate the total row count as it can take really a long time
>> to fetch all the records in a cluster and recommended to load off it to
>> something such as a map reduce job.
>>
>> to fetch 100,000 records it took 2.73 Seconds. So all together it takes
>> around 191 seconds to complete it.
>>
>> What would be the best way to overcome this ?
>>
>> Thanks
>>
>> --
>> *Shelan Perera*
>>
>> Software Engineer
>> **
>> *WSO2, Inc. : wso2.com*
>> lean.enterprise.middleware.
>>
>> *Home Page*  :    shelan.org
>> *Blog*             : blog.shelan.org
>> *Linked-i*n      :http://www.linkedin.com/pub/shelan-perera/a/194/465
>> *Twitter*         :https://twitter.com/#!/shelan
>>
>> *Mobile*          : +94 772 604 402
>>
>>
>>
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>
>
> --
> *Anjana Fernando*
> Associate Technical Lead
> WSO2 Inc. | http://wso2.com
> lean . enterprise . middleware
>
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>


-- 
Regards,

Tharindu

blog: http://mackiemathew.com/
M: +94777759908
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