[JCO.ServerThread-1] ERROR SERVER-EXCEPTION - [null,null,null,] com.sap.mw

Question

When we execute a SAP transaction through xMII, xMII server is brought down.
I looked in the cms.log file and found this:
<b><i><i>2007-10-16 11:07:23,355 [JCO.ServerThread-1] ERROR  SERVER-EXCEPTION - [null,null,null,] com.sap.mw.jco.JCO$Exception: (129) JCO_ERROR_SERVER_STARTUP: Server startup failed at Tue Oct 16 11:07:23 EDT 2007.
This is caused by either a) erroneous server settings, b) the backend system has been shutdown, c) network problems. Will try next startup in 64 seconds.</i></i></b>
When I try to log back onto xMII, I see the following: 
<b><i>Error Executing Transaction Status (500) Internal Server Error.</i></b>
I created a Business Logic Services transaction within XMII.  This BLS extracts data from AFPO Order Item table.  A Repeater loops through the RESPONSE output table, and executes a SAP Query to load the data into Oracle tables.
I also have a BLS that executes BAPI_PRODORD_GET_LIST. 
When I execute either one of these transactions, the system will fail with the above error when the amount of data being extracted reaches a specific number.
I have simplified the BLS to run a JCO block for BAPI_PRODORD_GET_LIST and a tracer block.  When I execute the BLS that executes BAPI_PRODORD_GET_LIST to retrieve 2,000 production orders, the transaction hangs.  After 30 minutes, I terminate the transaction so it won’t take the xMII server down again.  However, had I had a repeater to loop through the output and load into the oracle tables, the server goes down.
That’s my problem.  My other question to the problem is this. 
What are the limitations to the amount of data that can be extracted from SAP via xMII?  Excel spreadsheets can download 40,000 records.  You can write a SELECT * in any language and pull down 40,000 records.  What is going on?

Answer 1

David,
Just an FYI the error message that you have found is not connected to your BLS transaction but rather the default IDoc listener trying to connect to something that doesn't exist.  This listener will automatically start each time xMII starts, as a result you can set it up to connect to an RFC destination or delete the default configuration and it will go away. 
Now onto your issue; How many Production Orders are being returned from the BAPI?  How are you loading each of them into Oracle?  How much memory is allocated to ServletExec vs. How much is available on the machine?  By default xMII will limit all SQL/Tag queries to their <b>RowCount</b> with a max at 250k rows but this does not apply to the JCo call.
My suggestion here is to look for the other error message that pertains to your transaction which may reside in the ServletExec logs and not xMII, they can be found on your xMII machine here: http://localhost/servletexec/admin/login.jsp
Hope this helps.
Sam