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Posted to user@cassandra.apache.org by "Adaryl \"Bob\" Wakefield, MBA" <ad...@hotmail.com> on 2014/11/14 07:10:12 UTC

how wide can wide rows get?

I’m struggling with this wide row business. Is there an upward limit on the number of columns you can have?

Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics
913.938.6685
www.linkedin.com/in/bobwakefieldmba
Twitter: @BobLovesData 

Re: how wide can wide rows get?

Posted by Joe Ramsey <jo...@mac.com>.
You can have up to 2 billion columns but there are some considerations.  

This article might be of some help.

http://www.ebaytechblog.com/2012/08/14/cassandra-data-modeling-best-practices-part-2/#.VGWdT4enCS0 <http://www.ebaytechblog.com/2012/08/14/cassandra-data-modeling-best-practices-part-2/#.VGWdT4enCS0>




> On Nov 14, 2014, at 1:10 AM, Adaryl Bob Wakefield, MBA <ad...@hotmail.com> wrote:
> 
> I’m struggling with this wide row business. Is there an upward limit on the number of columns you can have?
>  
> Adaryl "Bob" Wakefield, MBA
> Principal
> Mass Street Analytics
> 913.938.6685
> www.linkedin.com/in/bobwakefieldmba
> Twitter: @BobLovesData


Re: Re[2]: how wide can wide rows get?

Posted by Takenori Sato <ts...@cloudian.com>.
We have up to a few hundreds of millions of columns in a super wide row.

There are two major issues you should care about.

1. the wider the row is, the more memory pressure you get for every slice
query
2. repair is row based, which means a huge row could be transferred at
every repair

1 is not a big issue if you don't have many concurrent slice requests.
Having more cores is a good investment to reduce memory pressure.

2  could cause very high memory pressure as well as poorer disk utilization.


On Fri, Nov 14, 2014 at 3:21 PM, Plotnik, Alexey <ap...@rhonda.ru> wrote:

>  We have 380k of them in some of our rows and it's ok.
>
> ------ Original Message ------
> From: "Hannu Kröger" <hk...@gmail.com>
> To: "user@cassandra.apache.org" <us...@cassandra.apache.org>
> Sent: 14.11.2014 16:13:49
> Subject: Re: how wide can wide rows get?
>
>
> The theoretical limit is maybe 2 billion but recommended max is around
> 10-20 thousand.
>
> Br,
> Hannu
>
> On 14.11.2014, at 8.10, Adaryl Bob Wakefield, MBA <
> adaryl.wakefield@hotmail.com> wrote:
>
>   I’m struggling with this wide row business. Is there an upward limit on
> the number of columns you can have?
>
> Adaryl "Bob" Wakefield, MBA
> Principal
> Mass Street Analytics
> 913.938.6685
> www.linkedin.com/in/bobwakefieldmba
> Twitter: @BobLovesData
>
>

Re[2]: how wide can wide rows get?

Posted by "Plotnik, Alexey" <ap...@rhonda.ru>.
We have 380k of them in some of our rows and it's ok.

------ Original Message ------
From: "Hannu Kröger" <hk...@gmail.com>>
To: "user@cassandra.apache.org" <us...@cassandra.apache.org>>
Sent: 14.11.2014 16:13:49
Subject: Re: how wide can wide rows get?

The theoretical limit is maybe 2 billion but recommended max is around 10-20 thousand.

Br,
Hannu

On 14.11.2014, at 8.10, Adaryl Bob Wakefield, MBA <ad...@hotmail.com>> wrote:

I’m struggling with this wide row business. Is there an upward limit on the number of columns you can have?

Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics
913.938.6685
www.linkedin.com/in/bobwakefieldmba<http://www.linkedin.com/in/bobwakefieldmba>
Twitter: @BobLovesData

Re: how wide can wide rows get?

Posted by Hannu Kröger <hk...@gmail.com>.
The theoretical limit is maybe 2 billion but recommended max is around 10-20 thousand. 

Br,
Hannu

> On 14.11.2014, at 8.10, Adaryl Bob Wakefield, MBA <ad...@hotmail.com> wrote:
> 
> I’m struggling with this wide row business. Is there an upward limit on the number of columns you can have?
>  
> Adaryl "Bob" Wakefield, MBA
> Principal
> Mass Street Analytics
> 913.938.6685
> www.linkedin.com/in/bobwakefieldmba
> Twitter: @BobLovesData