ABAP Data Flow fetch huge table Failure under ECC 4.7

Hi everyone, I have a strange problem.

SAP ECC 4.7

Data Services 4.2 SP10

I need to join BKPF (header) and BSEG (item) into a huge template table with more than 400 columns.

I put this join logic in a ABAP Data Flow like below:

Join Codition:

BSEG.BUKRS = BKPF.BUKRS

and BSEG.BELNR = BKPF.BELNR

and BSEG.GJAHR = BKPF.GJAHR

When I run this job, there is a ABAP RFC call failure.

However, I have knowledge on ABAP. When I debug the generated program, it shows the rfc function raise an expection with subrc = 2.

I have confirmed this issue will not happen in the following two cases:

1. Under ECC6.0 with the same job, it can complete successfully. Data Size is more than 3 million rows.

2. If I add some filters to limit the data size to 2000 rows, this job will be OK (ECC4.7).

I noticed the ABAP code is totally different between 6.0 and 4.7.

I guess there is some limation in RFC TABLES parameter.

Do you have any idea about this?