Slow initial load from DSO to Cube

Hello experts,

I make a initial load from DSO with about 10 million records to an infocube. I have a selection criteria on 0CALMONTH in the DTP and a dataflow with Transformation/InfoSource/Transformation. I have on startroutine in the first transformation with a LOOP WHERE condition on the SOURCE_PACKAGE.

DTP runs 3 times parallel for writing into the infocube.

The first try I have to stop because it need more than 36 hours. Around 40 to 60 minutes each data package.

Than I splitted the load in yearly parts. First I loades in this mode 4 years. First data package need 40 minutes and the others need 2-4 minutes each.

But than I see that a logic in the startroutine is wrong and I have to reload again. On this load EVERY data package need 40-60 minutes.

Every try we are the only one who runs processes on the system. What could happen that it makes sometimes such differents each data package?

Thanks for help!

Peter