Home > Coherence, Java, Oracle > Some explanations of Oracle Coherence console output

Some explanations of Oracle Coherence console output

I will explain some part of the console output that I shared in previous section.

Console Output

The first three rows are related the tangosol-coherence-override settings. This file is the part of Oracle Coherence configuration and it provides many features for Oracle Coherence Cache Server. Something like multicast parameter, tcp parameter..

As shown in above because of our project has tangosol-coherence-override.xml, coherence server uses this file. If this file does not exist in project folder ( src/config as in previous example ), coherence uses the default file which inside the coherence.jar as shown in below:

2012-08-15 03:57:07.976/0.652 Oracle Coherence <Info> (thread=main, member=n/a): Loaded operational configuration from “jar:file:/labs/wls1211/coherence_3.7/lib/coherence.jar!/tangosol-coherence.xml” 2012-08-15 03:57:08.075/0.752 Oracle Coherence <Info> (thread=main, member=n/a): Loaded operational overrides from “jar:file:/labs/wls1211/coherence_3.7/lib/coherence.jar!/tangosol-coherence-override-dev.xml” 2012-08-15 03:57:08.077/0.753 Oracle Coherence <D5> (thread=main, member=n/a): Optional configuration override “/tangosol-coherence-override.xml” is not specified 2012-08-15 03:57:08.081/0.757 Oracle Coherence <D5> (thread=main, member=n/a): Optional configuration override “/custom-mbeans.xml” is not specified.

You also see that which file is used for coherence cache configuration. As shown in below you see that coherence uses our coherence-cache-config file which under the src directory of project.

2012-08-15 04:38:31.548/1.081 Oracle Coherence GE <Info> (thread=main, member=n/a): Loaded cache configuration from "file:/home/oracle/labs/Coh_labs/workspace/CohExam_AFSungur/src/config/coherence-cache-config.xml"

Another important point that we have a warning as you see in the console. These warnings are related the socket buffer parameters in linux. So far I haven’t changed any linux parameter yet but to clear warnings I will have to do a few. If you didn’t see any socket related warning pass this section.

To increase the socket buffer size in linux you should follow these steps:
edit the /etc/sysctl.conf file and add two lines to the file, before adding check the file whether it has written already or not

# increase TCP max buffer
  net.core.rmem_max = 16777216
 net.core.wmem_max = 16777216

After editing you should reload the settings, to do this

[root@localhost ~]# /sbin/sysctl -p

After run that you will see the changed parameter.

And let’s go back to the console, we see the TCMP and cluster-name. TCMP is a protocol that Coherence uses. It has many features like multicast communication, unicast communication and recognize new server which has just joined the cluster or the server which has just dropped from cluster.

Cluster-name parameter provides a name to the cluster so you can create multiple cluster on the same network. In our example cluster-name something like weird hex characters. Because we didn’t imply any name to the cluster. To give a name to the cluster edit the tangosol-coherence-override.xml file and add this lines:

         <cluster-name system-property="tangosol.coherence.cluster">

After it is added to tangosol-coherence-override.xml rerun the application and cache servers then you’ll see this output:

2012-08-15 04:38:35.707/5.240 Oracle Coherence GE <Info> (thread=Cluster, member=n/a): Created a new cluster "MyFirstCluster" with Member(Id=1, Timestamp=2012-08-15 04:38:32.417, Address=, MachineId=2063, Location=site:,process:4244, Role=AfsungurCoherenceCustomerTest1, Edition=Grid Edition, Mode=Development, CpuCount=1, SocketCount=1) UID=0x0A00020F000001392A13EC61080F1F98
2012-08-15 04:38:35.712/5.245 Oracle Coherence GE <Info> (thread=main, member=n/a): Started cluster Name=MyFirstCluster

As shown in above there are many attributes which are shared. For example you see that IP address of client, machine id, member id ( this is so useful when you design your load balancing mechanism ), cpu and socket count, role information. Cpu and socket count parameters are 1 because I run coherence on VM within a single cpu.  Role name  allows an application to get together coherence members into special roles. For example cache clients and cache servers. And site name ( location ) provides intelligent routing, load balancing and  disaster recovery planning while you are using WAN clustering, that’s really cool.

In the MasterMembetSet section there are information about the members which are connected the cluster.

And the bottom of the console you see that PofConfiguration is loaded from the file which is under the src/config folder of the project.

  1. August 29, 2012 at 10:03 am

    Nice post

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