How to find if a COBOL program is looping, thru Mainview

If you want to know if a program is looping (on mainframe) and if you have Mainview for MVS, then
1. Go to JCPUR which shows realtime job CPU utilization
2. Place the cursor on the job you are interested in and hit enter
3. It'll take you to EZMJOBR window
4. Under SYSPROG Service, you'll find "MVScope CPU Tracing". Place your cursor there and hit enter
5. Then place your cursor on "Begin CPU Trace" and hit enter. It'll start CPU tracing.
6. Once it finishes, see if it shows any one particular statement. If so, it could mean, the program was in a loop during the trace period.
7. Get the Offset info, go to the compile listing and search for the Offset under HEXLOC (you may not find the exact offset, but the one just before this value is good enough). Get the line number and get the statement that was in loop.

Simple?

Mainview Tips

Here are some tips if you are an user of Mainview for z/OS

• VIEWS command gives you a list of all the VIEWs installed/available
• Use CON xyza, where xyza is the LPAR name, command to connect to the xyza LPAR
• Use MSG msgnumber command to get an explanation on the Error Messages displayed by Mainview. e.g., msg BBMXC739
• Use CUST command to customize a VIEW
• Use ASU command to update all windows automatically at a particular frequency (similar to the "&n" command in SDSF)
• SYSSUM view shows how busy the LPAR has been in the prev intervals
• To bring up multiple windows, use HS (Horizontal Split) or VS (VerticalSplit) to split the screen as required
• Use CLO n, where n is the window number, to close a window
• Use Wn;MAX to maximize window number 'n'
• Use Wn;REST to restore the window to it's original size
• Type SCREENS to see all the user defined screens
• Use SCR screenname to jump to a user defined screen
• To create your own screen, format the window as desired (multiple windows connecting to different systems etc.) and then type SAVESCR screenname
• Summary VIEWs end with letter Z. e.g., JCPUZ
• Long Term History data VIEWs end with letter L. e.g., JCPUL
• If you are in a view like JCPUZ, you can scroll back and forth in time using the command TIME. Type TIME after getting into JCPUZ. Type 'TIME = = NEXT' to go to the NEXT interval and type 'TIME = = PREV' to go to the PREVious interval without changing the interval data and time. Also, you can assign them to PF keys.