connect failed: reached maximum number of connections 0

Question

the max_connections property is set to 0 (unlimited number of connections) but still the ems server keeps on spitting out this to tibemsd.log

[admin:somehost]: connect failed: reached maximum number of connections 0

how can this be possible?

Thanks!

Answer 1

For anyone interested,

it appears that there is a limit of maximum 256 admin connections that can be open concurrently to the ems server. This limit is apparently not controlled by the max_connections property for some reason.

Here is a small example to verify this.

import com.tibco.tibjms.admin.TibjmsAdmin;
public class AdminConnectionTest{
 public static void main(String args[}){
  int counter =0;
  try{  
   for(int i=0;i<1000;i++){
   TibjmsAdmin admin = new TibjmsAdmin("tcp://localhost:7222","someuser","someuser");
   counter++;
   }

  }catch(Exception e){
   System.out.println( "Connections created: "+counter);
   System.out.println( e.getMessage());
   try{
    Thread.sleep(20000); //Some delay to make it possible to verify this from emsadmin
   }catch(Exception ee){System.out.println( ee.getMessage());}
  }
 }
}

Answer 2

To protect on the client side from overloading the server with connections, I wrote a simple commons pool2 class.

import com.tibco.tibjms.admin.TibjmsAdmin;
import com.tibco.tibjms.admin.TibjmsAdminException;
import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.PooledObjectFactory;
import org.apache.commons.pool2.impl.DefaultPooledObject;

public class TibcoAdminPoolableObjectFactory implements PooledObjectFactory<TibjmsAdmin>{
    @Override
    public PooledObject<TibjmsAdmin> makeObject() throws Exception {
        TibjmsAdmin admin = new TibjmsAdmin("tcp://tibco:7222","USER","password");
        return new DefaultPooledObject<>(admin);
    }
    @Override
    public void destroyObject(PooledObject<TibjmsAdmin> po) throws Exception {
        po.getObject().close();
    }
    @Override
    public boolean validateObject(PooledObject<TibjmsAdmin> po) {
        try {
            po.getObject().getQueue("xyzabc");
        } catch (TibjmsAdminException ex) {
            System.out.println(ex.getMessage());
            return false;
        }
        return true;
    }
    @Override
    public void activateObject(PooledObject<TibjmsAdmin> po) throws Exception {}
    @Override
    public void passivateObject(PooledObject<TibjmsAdmin> po) throws Exception {}
}

GenericObjectPool<TibjmsAdmin> pool = new GenericObjectPool<>(new TibcoAdminPoolableObjectFactory());
TibjmsAdmin admin = pool.borrowObject();
QueueInfo infos[] = admin.getQueues("YOURQUEUE");
pool.returnObject(admin);//in a finally block