On 9/9/16, 8:47 AM, "Rakesh Kumar" <rakeshkumar46...@gmail.com> wrote:

>> If your partition sizes are over 100MB iirc then you'll normally see
>> warnings in your system.log, this will outline the partition key, at least
>> in Cassandra 2.0 and 2.1 as I recall.
>
>Has it improved in C* 3.x. What is considered a good partition size in C* 3.x

In modern versions (2.1 and newer), the “real” risk of large partitions is that 
they generate a lot of garbage on read – it’s not a 1:1 equivalence, but it’s 
linear, and a partition that’s 10x as large generates 10x as much garbage.

You can tune around it (very large new gen, for example), but it’s best fixed 
at the data model most of the time.

The long term fix will be Cassandra-9754, which is a work in progress. The 
short term fix for 3.x was http://issues.apache.org/jira/browse/CASSANDRA-11206 
, which went into 3.6 and higher

In the notes on 11206, you’ll see that Robert Stupp tested up to an 8GB 
partition – while nobody’s going to recommend you create a data model with 8gb 
partitions, I imagine you may find partitions in that rough order of magnitude 
acceptable.

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