Cube Processing - Aggregations

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Cube Processing - Aggregations

VALEK

SSCarpal Tunnel

Points: 4206
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September 24, 2008 at 4:07 pm

#191411

Hi all,
I have a cube, which is build on an around 1mnl record table. It also has some 20 dimensions.
I designed aggregations using the wizard in BIDS.
When I process the cube it reads the fact table, and then starts circling around aggregation processing. What I mean here is that it goes from 1 to 40 for example then jumps back to 20 and starts again, then jumps back and over and over again.
This happens like 10-20 times, before if finally completes and writes the cube on disk. The whole process takes some 30-40 minutes, which is ridiculously long.
What is SSAS doing here and is there any way I can speed up cube processing?
Cheers,
VAL
M.Sc.IT, M.B.A, MCTS BI 2008, MCITP BI 2008, MCTS SQL Dev, CSM, CDVDM

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elegantkvc SSCommitted Points: 1910 More actions · Answer 1

hi,

Try the possibility of using perspectives in the cube.It will definetly speed up the cube processing.

cheers

vijay

VALEK SSCarpal Tunnel Points: 4206 More actions · Answer 2

elegantkvc (10/3/2008)
hi,
Try the possibility of using perspectives in the cube.It will definetly speed up the cube processing.
cheers
vijay

Thank you for the advice, but I would like to know WHAT exactly SSAS is doing when processing and going back-and-forth.

And again -- if I implement perspectives, what will change?

And also -- what exactly I need to do with the perspectives to speed up the processing? I do not need perspectives really...

Cheers

VAL

M.Sc.IT, M.B.A, MCTS BI 2008, MCITP BI 2008, MCTS SQL Dev, CSM, CDVDM

kcj Mr or Mrs. 500 Points: 540 More actions · Answer 3

Did you create proper attribute relationships in your diemnsions?

wildh SSCarpal Tunnel Points: 4370 More actions · Answer 4

You have probably seen this already "download.microsoft.com/download/8/5/e/85eea4fa-b3bb-4426-97d0-7f7151b2011c/SSAS2005PerfGuide.doc" (SSAS performance Guide)

But the section “How to impact aggregation design” could remind you of something’s you may have forgotten about eg. Maybe its time to counts? When was the last time you did it?

It doesn’t go into the nitty gritty of your original question of what’s going on but it will probably be something to do with the cost/benefit algorithm SSAS uses and the information about the fact/ attribute counts and overall design it uses.

Hope this is a point in the right direction or at lease a help, and if you do find something that explains it well please share as I know I would be interested.