I used 'ora_plogon' function like this
    $conn = ora_plogon( $id, $pass );

In the same page, I try another connection to oracle
 at remote system like 
    $conn2 = ora_plogon( $id@MYTNS , $pass );

It works well at this time!!


But... 
  When I use $conn (first connection ) in some operation.
  It works as $conn2.. 
So to speak, when I use 'select..' with $conn.. ,it (php)
  finds table in remote system ...

This occurs sometimes not always..

SID and ORACLE_HOME enviroment variable are same in both
system.


I think that pconnect in oracle has some bugs...