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From Janne Jalkanen <>
Subject Re: Cassandra Data Stax java driver & Snappy Compression library
Date Sun, 02 Aug 2015 06:50:23 GMT
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


> On 02 Aug 2015, at 02:17 , Sachin Nikam <> 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 --
> <>
> #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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