No, this just tells that your client (S3 using Datastax driver) cannot 
communicate to the Cassandra cluster using a compressed protocol, since the 
necessary libraries are missing on the client side.  Servers will still 
compress the data they receive when they write it to disk.

In other words

Client  <- [uncompressed data] -> Server <- [compressed data] -> Disk. 

To fix, make sure that the Snappy libraries are in the classpath of your S3 
service application.  As always, there’s no guarantee that this improves your 
performance, since if your app is already CPU-heavy, the extra CPU overhead of 
compression *may* be a problem.  So measure :-)

/Janne

> On 02 Aug 2015, at 02:17 , Sachin Nikam <skni...@gmail.com> wrote:
> 
> I am currently running a Cassandra 1.2 cluster. This cluster has 2 tables i.e.
> TableA and TableB.
> 
> TableA is read and written to by Services S1 and S2 which use Astyanax client 
> library.
> 
> TableB is read and written by Service S3 which uses the datastax java driver 
> 2.1. S3 also reads data from TableA.
> 
> Both TableA and TableB are defined on the Cassandra nodes to use 
> SnappyCompressor.
> 
> On start-up service, Service S3 throws the following WARNing messages. The 
> service is able to continue doing its normal operation thereafter
> 
> **************
> [main] WARN  loggerClass=com.datastax.driver.core.FrameCompressor;Cannot find 
> Snappy class, you should make sure the Snappy library is in the classpath if 
> you intend to use it. Snappy compression will not be available for the 
> protocol.
> ***********
> 
> 
> My questions are as follows--
> #1. Does the compression happen on the cassandra client side or within 
> cassandra server side itself?
> #2. Does Service S3 need to pull in additional dependencies for Snappy 
> Compressions as mentioned here --
> http://stackoverflow.com/questions/21784149/getting-cassandra-connection-error
>  
> <http://stackoverflow.com/questions/21784149/getting-cassandra-connection-error>
> #3. What happens without this additional library not being present on class 
> path of Service S3. Any data that S3 writes to TableB will not be compressed? 
> Regards
> Sachin

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