Strange behavior in parallel processing (aRFC)

Hi,

I have a requirement to post GL per day 1.5 to 3 Million(1500000 records to 3000000). I have to read file form SAP AS and do some preliminary validations like mapping, delete errors records (not required to post), etc...,

Now I have developed a RFC Function Module calling with Parallel processing. With in this function calling BAPI for posting documents.

When I am posting with 100000 to 300000 lacks there is no problem which faster and posting document. But when I scheduled with more than 1.5 million then Parallel Processing ARFC behaving improper.

Could anyone help me what is the cause/error in my program.

Thanks in advance.

Thanks,

Yerukala Setty