sqlplus -prelim used for hang analysis

C:\Users\jayva>set ORACLE_SID=target

C:\Users\jayva>sqlplus /nolog

SQL*Plus: Release 11.2.0.1.0 Production on Tue Jun 5 19:56:09 2012

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

SQL> set _prelim on

SQL> conn / as sysdba

Prelim connection established

SQL> oradebug setmypid

Statement processed.

SQL> oradebug hanganalyze 12

Statement processed.

SQL> exit

Disconnected from ORACLE

C:\Users\jayva>sqlplus -prelim /nolog

SQL*Plus: Release 11.2.0.1.0 Production on Tue Jun 5 19:57:05 2012

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

SQL> connect / as sysdba

Prelim connection established

SQL> oradebug setmypid

Statement processed.

SQL> oradebug hanganalyze 12

Statement processed.

SQL> exit

Disconnected from ORACLE

C:\Users\jayva>