When ora_logon fails to establish a connection because the Oracle 7.1.3 database is unavailable,
I get defunct Apache (1.3.12) processes stacking up for every logon attempt:

     UID   PID  PPID   C    STIME    TTY  TIME CMD
     web  7730 23752   1                  0:00 <defunct>
     web  9386  8762   2                  0:00 <defunct>
     web  9556  8762   1                  0:00 <defunct>
     web 13638 40776   1                  0:00 <defunct>
     web 15614 33948   1                  0:00 <defunct>
....

This keeps happening until I run out of available processes or I catch it and shutdown Apache.

I'm testing to see if a connection was established before proceeding with other Oracle function calls.

   $conn = ora_logon($oracleAccount, $oraclePassword); 
   if ($conn != false) {
    // do oracle stuff here
   } else {
    // display error messsage
   }

I don't have this problem as long as the Oracle db is available.