Inventory Management Loading clarification - loading BX , BF and UM

Question

Hi,
I want to load inventory management from scratch.
I have ready lots of documents from this site related to this but still unsure.
In SAP document, It says that BX should be compressed with NO MARKER UPDATE and  while BF and UM should be compressed with NO MARKER Update box checked.
I also read some where that
BX and UM should be compressed with No marker update not selected while only BF should be compressed with marker update box checked.
which is the correct version or whats the difference between these two.
thanks

Answer 1

Hi Vaidya,
Inventory calculate all non cumulative values based on a reference +/- delta principle.
The reference is called the marker.
Answer to the question when should I do a marker update?
Initially, for first load to BW, if R/3 system has gone live earlier, each material would have some stock value in the plant. But if BW has to load only deltas , then it should have this initial stock figures.
So we do a statsitcal run for BX. This statistical run.. consider intial stock of R/3 when it went live + incoming material movement documents - outgoiong material movements and loads BX.
So after this load in BW, we compress the request in BW to create our marker to say 100PCS for material A in plant A as on 31.03.2009.
Now if you are interested in seeing on what were material movements(incoming/outgoing)  for 01.02.2009 in BW, you would have to load BF to BW.
So you rean intialization for BF and loaded BF in BW.
But this movement of material A on 01.02.2009 was considered in getting our marker value when we did BX load. This is because in our statistical run for BX we had calculated = R/3 initail stock + incoming movements - outgoing movements until 31.03.2009. So if we consider this historical movement for marker uppdae again our marker would become incorrect.
So when we load BF until 31.03.2009(initialization run) we do not update the marker. So we compress the marker without update.
From 31.03.2009 onward when you load detlas to BW for BF and UM every day, you would like to update the marker to keep it current as of date.
ie say material A moved out on 01.04.2009 - 20 pcs.
say material A moved in on 03.04.2009 - 40 pcs.
So on 4th when you load delta and update the marker , the marker value would be - 100 - 20 + 40 =120.
You update the marker because business is most often interested to see stock of previous or two to three days before. If the marker is updated then it has to check fewer records to get the delta to goe the the stock figure then.
Thus, for all future delta loads you would compress with marker update.
Hope this helps,
Best regards,
Sunmit.