Duffbert's Random Musings

Document Number:  1109686

Problem

How can you determine whether a LotusScript agent is leaking memory?

Content
** Note**:        This technote should be distributed on an as-needed basis only - specifically, only when either you or a customer suspects that there are memory leaks in a LotusScript agent.  The agents included below are intended to be used only to identify memory leaks in a LotusScript agent.

If you suspect that a LotusScript agent is leaking memory, use one of the following scripts to determine whether memory is indeed not being freed once the agent finishes executing.

The following scripts monitor allocated memory for each thread.  Each executive process takes up one thread.  You need to be aware of this as you are troubleshooting - because the values may change when a different executive process runs your agent than the last time it was run.  When more than one executive process is being run on the sever, there is no way to control which thread the memory check agent will run on.  If it runs on a thread other than the thread that the leaking agent ran on, then the output is irreverent.  When possible, it may be best to limit the number of executive processes (set in the Server document) to 1 while troubleshooting the leak.

Each memory-checking script should be placed in an agent to execute before the agent in question and again after the agent in question.  Compare the two sets of numbers.  If the second set of numbers is higher, all memory has not been freed.

If a memory leak is found, isolate the pieces of the code that are leaking.  One way to do this is to break up the code into smaller pieces.  Execute the appropriate leak-checking agent, then execute the modified agent, then execute the leak-checking agent again.

Leak-Checking Agents:

I.  If the agent is running in the fore-ground, use the following code:

Sub Initialize  
    Msgbox(" Total LotusScript Memory Allocated: " + (Lsi_info(50)))
    Msgbox(" Total LotusScript Memory Allocated from OS: " + (Lsi_info(51)))
    Msgbox(" Total LotusScript Blocks Used: " + (Lsi_info(52)))    
End Sub

This agent displays a message box showing the amount of memory allocated via LotusScript.  Remember to run this code immediately before and after you execute the agent in question - to compare values and determine whether the agent is indeed leaking memory.

II. If the agent is scheduled, use the following code:

Sub Initialize  
     Print "Total LotusScript Memory Allocated: " + Str$(Lsi_info(50)) + Chr$(10) + Chr$(13)
    Print "Total LotusScript Memory Allocated from OS: " + Str$(Lsi_info(51)) + Chr$(10) + Chr$(13)
    Print "Total LotusScript Blocks Used: " + Str$(Lsi_info(52)) + Chr$(10) + Chr$(13)
End Sub

This agent writes to the server's LOG.NSF file.  Remember to run this code immediately before and after the agent in question - to compare values and determine whether the agent is indeed leaking memory.