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From Umang Shah <shahuma...@gmail.com>
Subject Re: What will be system configuration for retrieving few "GB" of data
Date Sun, 19 Oct 2014 08:12:33 GMT
Thanks Mohammed.. This the Answer which i am looking for.

Regards,
Umang Shah

On Sat, Oct 18, 2014 at 5:11 AM, Mohammed Guller <mohammed@glassbeam.com>
wrote:

>  With 8GB RAM, the default heap size is 2GB, so you will quickly start
> running out of heap space if you do large reads. What is a large read? It
> depends on the number of columns in each row and data in each column. It
> could 100,000 rows for some and 300,000 for others. In addition, remember
> that Java adds a lot of overhead to data in memory, so a 8 character string
> will not occupy just 8 bytes in memory, but a lot more.
>
>
>
> In general, avoid large reads in C*. If it is absolutely must and you
> cannot repartition the data, then use a driver that supports paging.
>
>
>
> Mohammed
>
>
>
> *From:* Umang Shah [mailto:shahumang4@gmail.com]
> *Sent:* Wednesday, October 15, 2014 10:46 PM
> *To:* user@cassandra.apache.org
> *Subject:* What will be system configuration for retrieving few "GB" of
> data
>
>
>
> Hi,
>
>
>
> I am facing many problem after storing certain limit of records in
> cassandra, and giving outofmemoryerror.
>
>
>
> I have 8GB of RAM in my system, so how much records i can expect to
> retrieve by using select query?
>
>
>
> and what will be the configuration for those people who are retrieving
> 15-20 GB of data?
>
>
>
> Can somebody explain me how to improve read performance then it will be
> great help, i tried
>
>
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/operations/ops_tune_jvm_c.html
>
>
>
> such things but no help.
>
>
>
>
>
> --
>
> Regards,
>
> Umang Shah
>
> shahumang4@gmail.com
>



-- 
Regards,
Umang V.Shah
+919886829019

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