Correct. Note that you may lose some performance this way though; in a typical case saving bandwidth by increasing CPU usage is good. However, it always depends on your usecase and whether you’re running your cluster to the max. It’s a good, low-hanging optimization to keep in mind though for production environments, if you choose not to enable compression now.
/Janne > On 3 Aug 2015, at 08:40, Sachin Nikam <skni...@gmail.com> wrote: > > 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.jalka...@ecyrd.com > <mailto:janne.jalka...@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 <skni...@gmail.com >> <mailto: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 > >
