Why the extraction will be excuted serveral times when I create datasource by Funcion Module

Hi Guys

I created a datasource by using function module.

But there is something coufused me.

When I use infopackage to load the data from ecc to bw

There will be serveral data packages which contains same data.

Actually, It should be one data package contain all data. But now I have serveral duplicate.

Below is the code.

I combined MBEW MCHA By materail(MATNR),Plant(BWKEY)and BWTAR.

Actually, I don't need the rsa3 to test (I don't know how to avoid this part in the code,but have to write something I don't think necessary).So I used "Refresh E_T_DATA" in the code.