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From Sachin Nikam <skni...@gmail.com>
Subject Re: Cassandra Data Stax java driver & Snappy Compression library
Date Mon, 03 Aug 2015 05:40:37 GMT
Thanks Janne...
To clarify, Service S3 should not run in to any issues and I may choose to
not fix the issue?
Regards
Sachin

On Sat, Aug 1, 2015 at 11:50 PM, Janne Jalkanen <Janne.Jalkanen@ecyrd.com>
wrote:

> 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 <sknikam@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
> #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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