It involves the handling of two Msg Types: CONF21 and WMMXBXY. I'm not a Basis person, so please bear with me....
As in 4.0, one instance was established to support both transactions, but processing the Msg Type CONF21 the application failed due to the lack of resources.
When a second application server instance is initiated, CONF21 processes okay, but when more than one WMMBXY is processed, the second transaction gets flagged due to the first having locked the material.
I increased the "number of repeats" for the FM to 10, but I think the real issue is related to needing more than one instance. Any suggestions will be welcomed.
You should make sure that the IDocs are processed sequentially. This can be achieved by serializing the IDocs (setting a unique serial number in the IDoc header record in field EDIDC-SERIAL). Then the second IDoc in sequence is only processed when the first IDoc has finished processing.
Another solution would be to set the partner profile for the IDoc to "batch processing" and then process them by calling regularly RBDAPPIN in a batch job. This will also execute one IDoc after the other.
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