Poor performance with WebI and BW hierarchy drill-down...

Question

Hi
We are currently implementing a large HR solution with BW as backend
and WebI and Xcelcius as frontend. As part of this we are experiencing
very poor performance when doing drill-down in WebI on a BW hierarchy.
In general we are experiencing ok performance during selection of data
and traditional WebI filtering - however when using the BW hierarchy
for navigation within WebI, response times are significantly increasing.
The general solution setup are as follows:
1) Business Content version of the personnel administration
infoprovider - 0PA_C01. The Infoprovider contains 30.000 records
2) Multiprovider to act as semantic Data Mart layer in BW.
3) Bex Query to act as Data Mart Query and metadata exchange for BOE.
All key figure restrictions and calculations are done in this Data Mart
Query.
4) Traditionel BO OLAP universe 1:1 mapped to Bex Data Mart query. No
calculations etc. are done in the universe.
5) WebI report with limited objects included in the WebI query.
As we are aware that performance is an very subjective issues we have
created several case scenarios with different dataset sizes, various
filter criteria's and modeling techniques in BW.
Furthermore we have tried to apply various traditional BW performance
tuning techniques including aggregates, physical partitioning and pre-
calculation - all without any luck (pre-calculation doesn't seem to
work at all as WebI apparently isn't using the BW OLAP cache).
In general the best result we can get is with a completely stripped WebI report without any variables etc.
and a total dataset of 1000 records transferred to WebI. Even in this scenario we can't get
each navigational step (when using drill-down on Organizational Unit
hierarchy - 0ORGUNIT) to perform faster than minimum 15-20 seconds per.
navigational step.
That is each navigational step takes 15-20 seconds
with only 1000 records in the WebI cache when using drill-down on org.
unit hierachy !!.
Running the same Bex query from Bex Analyzer with a full dataset of
30.000 records on lowest level of detail returns a threshold of 1-2
seconds pr. navigational step thus eliminating that this should be a BW
modeling issue.
As our productive scenario obviously involves a far larger dataset as
well as separate data from CATS and PT infoproviders we are very
worried if we will ever be able to utilize hierarchy drill-down from
WebI ?.
The question is as such if there are any known performance issues
related to the use of BW hierarchy drill-down from WebI and if so are
there any ways to get around them ?.
As an alternative we are currently considering changing our reporting
strategy by creating several higher aggregated reports to avoid
hierarchy navigation at all. However we still need to support specific
division and their need to navigate the WebI dataset without
limitations which makes this issue critical.
Hope that you are able to help.
Thanks in advance
/Frank
Edited by: Mads Frank on Feb 1, 2010 9:41 PM

Answer 1

Hi Henry, thank you for your suggestions although i´m not agree with you that 20 seconds is pretty good for that navigation step. The same query executed with BEx Analyzer takes only 1-2 seconds to do the drill down.
Actions
suppress unassigned nodes in RSH1: Magic!! This was the main problem!!
tick use structure elements in RSRT: Done it.
enable query stripping in WebI: Done it.
upgrade your BW to SP09: Has the SP09 some inprovements in relation to this point ?
use more runtime query filters. : Not possible. Very simple query.
Others:
RSRT combination H-1-3-3-1 (Expand nodes/Permanent Cache BLOB)
Uncheck prelimirary Hierarchy presentation in Query. only selected.
Check "Use query drill" in webi properties.
Sorry for this mixed message but when i was answering i tryied what you suggest in relation with supress unassigned nodes and it works perfectly. This is what is cusing the bottleneck!! incredible...
Thanks a lot
J.Casas