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From aaron morton <aa...@thelastpickle.com>
Subject Re: Wide row column slicing - row size shard limit
Date Thu, 16 Feb 2012 08:38:19 GMT
> 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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