wangwenli created HADOOP-12529:
----------------------------------

             Summary: UserGroupInformation equals method depend on the subject 
object address
                 Key: HADOOP-12529
                 URL: https://issues.apache.org/jira/browse/HADOOP-12529
             Project: Hadoop Common
          Issue Type: Bug
          Components: security
    Affects Versions: 2.7.1
            Reporter: wangwenli



 my question is    why UserGroupInformation equals method depend on the subject 
object?


       try below code which is extract from HiveMetaStore:
{code:title=TestUgi.java|borderStyle=solid}
UserGroupInformation clientUgi = null;
UserGroupInformation clientUgi2 = null;
try {
clientUgi = UserGroupInformation.createProxyUser("user2", 
UserGroupInformation.getLoginUser());
clientUgi2 = UserGroupInformation.createProxyUser("user2", 
UserGroupInformation.getLoginUser());
if (clientUgi.equals(clientUgi2)) {
System.out.println("==");
} else {
System.out.println("!=");           //  strangely  this will be hit
}
} catch (IOException e1) {
e1.printStackTrace();
}
{code}
      i found that it is because the equal method from UserGroupInformation is 
compare on subject object ref : subject == ((UserGroupInformation) o).subject;  
.    

     as you know,   ipc.Client connect to namenode,   
connections.get(ConnectionId)    this code will try to reuse the same socket to 
namenode, but because of ConnectionId's equal depend on ugi equal, which will 
cause connections.get(ConnectionId) cann't get the same socket,   suppose many 
connect to HiveMetaStore, then many connection to Namenode will established.

      so my doubts is why UserGroupInformation is compare on subject object ref 
: subject == ((UserGroupInformation) o).subject,   it should compare on 
subject's principal,  am i right?



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to