why is very slow to connect to cassandra cluster in cloud from local application using c# driver?

[Hongwei Liu]

hi,

my application solution is :

   - three cassandra nodes running in Windows Azure Virtual Machine, under hosted service 'http://xxx.cloudapp.net'

   - a local windows service written with c#, which use cassandra c# driver to manage data in the cassandra cluster

in the client application :

var Host = "xxx.cloudapp.net";

var User = "yyy";

var Password = "zzz";

var cluster = Cluster.Builder().AddContactPoint(Host)

                            .WithCompression(CompressionType.Snappy)

                            .WithLoadBalancingPolicy(new RoundRobinPolicy())

                            .WithCredentials(User, Password).Build();

var session = cluster.Connect();

but the call of 'cluster.Connect()' always takes about 3 to 5 minutes. 

this is quite slow. 

i want to know what cause this. 

how can i improve this? (i can cache the session for next use, but the first time to establish the connection is really quite slow)

Thanks in advance for your helps.

Hongwei

[Jorge Bay Gondra]

Hi,

You can diagnose the connectivity issue by enabling tracing: 

// Specify the minimum trace level you want to see
Cassandra.Diagnostics.CassandraTraceSwitch.Level = TraceLevel.Info;
// Add a standard .NET trace listener
Trace.Listeners.Add(new ConsoleTraceListener());

http://docs.datastax.com/en/developer/csharp-driver/2.5/csharp-driver/csdFaq.html

Cheers,

Jorge

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[Adin Aronson]

This was really helpful information. I can see that when I connect to Cassandra's external IP I can a bunch of local IPs that the driver is trying to connect to and can't (since they are in the cloud) I wonder how this can be solved...

On Monday, May 18, 2015 at 10:00:25 AM UTC+3, Jorge Bay Gondra wrote:

Hi,

You can diagnose the connectivity issue by enabling tracing: 

// Specify the minimum trace level you want to see
Cassandra.Diagnostics.CassandraTraceSwitch.Level = TraceLevel.Info;
// Add a standard .NET trace listener
Trace.Listeners.Add(new ConsoleTraceListener());

http://docs.datastax.com/en/developer/csharp-driver/2.5/csharp-driver/csdFaq.html

Cheers,

Jorge

On Fri, May 15, 2015 at 7:49 PM, Hongwei Liu <albert.h...@gmail.com> wrote:

hi,

my application solution is :

   - three cassandra nodes running in Windows Azure Virtual Machine, under hosted service 'http://xxx.cloudapp.net'

   - a local windows service written with c#, which use cassandra c# driver to manage data in the cassandra cluster

in the client application :

var Host = "xxx.cloudapp.net";

var User = "yyy";

var Password = "zzz";

var cluster = Cluster.Builder().AddContactPoint(Host)

                            .WithCompression(CompressionType.Snappy)

                            .WithLoadBalancingPolicy(new RoundRobinPolicy())

                            .WithCredentials(User, Password).Build();

var session = cluster.Connect();

but the call of 'cluster.Connect()' always takes about 3 to 5 minutes. 

this is quite slow. 

i want to know what cause this. 

how can i improve this? (i can cache the session for next use, but the first time to establish the connection is really quite slow)

Thanks in advance for your helps.

Hongwei

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[Joao Reis]

Hi,

Are you setting the "rpc_address" property in the node's cassandra.yaml? Here's some documentation on this topic: https://docs.datastax.com/en/developer/csharp-driver/latest/features/address-resolution/

If you have multiple nodes that can not be accessed from the network where the application is running, then I would suggest providing a custom load balancing policy (like java driver's HostFilterPolicy). Keep in mind that query routing will not be optimal and performance will take a hit so you should not do this in production.

Best regards,

João Reis |  Senior Software Engineer - Drivers

joao...@datastax.com  |  datastax.com

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[Adin Aronson]

Hi Joao,

I figured out to use the Cluster.Builder().WithAddressTranslator(new ToPublicIpAddressTranslater()) option. Inside ToPublicIpAddressTranslater() I translated the local IPs to external IPs and this solved all my issues but I never would have even known about them if I hadn't come across your post about using Trace.

Thanks,

Adin