> Based on this blog of Basic Time Series with Cassandra data modeling,
> http://rubyscale.com/blog/2011/03/06/basic-time-series-with-cassandra/
I've not read that one but it sounds right. Mat Dennis knows his stuff  
http://www.slideshare.net/mattdennis/cassandra-nyc-2011-data-modeling  

> There is a limit on how big the row size can be before slowing down the 
> update and query performance, that is 10MB or less.
There is no hard limit. Wide rows wont upset writes too much. Some read queries 
can avoid problems but most will not. 

Wide rows are a pain when it comes to maintenance.  They take longer to compact 
and repair. 

> Is this still true in Cassandra latest version? or in what release Cassandra 
> will remove this limit?
There is a limit of 2 billion columns per row. There is a not a limit of 10MB 
per row. I've seen some rows in the 100's of MB and they are always a pain. 

> Manually sharding the wide row will increase the application complexity, it 
> would be better if Cassandra can handle it transparently.
it's not that hard :)

Cheers

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

On 16/02/2012, at 7:40 AM, Data Craftsman wrote:

> Hello experts,
> 
> Based on this blog of Basic Time Series with Cassandra data modeling,
> http://rubyscale.com/blog/2011/03/06/basic-time-series-with-cassandra/
> 
> "This (wide row column slicing) works well enough for a while, but over time, 
> this row will get very large. If you are storing sensor data that updates 
> hundreds of times per second, that row will quickly become gigantic and 
> unusable. The answer to that is to shard the data up in some way"
> 
> There is a limit on how big the row size can be before slowing down the 
> update and query performance, that is 10MB or less.
> 
> Is this still true in Cassandra latest version? or in what release Cassandra 
> will remove this limit?
> 
> Manually sharding the wide row will increase the application complexity, it 
> would be better if Cassandra can handle it transparently.
> 
> Thanks,
> Charlie | DBA & Developer
> 
> 
> p.s. Quora link,
> http://www.quora.com/Cassandra-database/What-are-good-ways-to-design-data-model-in-Cassandra-for-historical-data
> 
> 
> 

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