Thursday, February 21, 2013

Limit on cubes per multiprovider ?

Sometimes BW developers are keen on to reach limits of BW. Like they want to try what are limits from any angle of BW. The angle may really very vary. Very common BW limits know to every developer are on term of no of InfoObjects (248) per dimension, no (233) Key figures in cube, no (13) of custom Dimensions (3 by default:  request, time, and unit). Also there can be no more than 2 billion ( SIDs for one single IO. Therefore there can only be a max of 2 billion different values for the respective characteristic (note 1331403). Another example would be no of attributes that characteristic can have (was 250 attributes in BW 2.0 and 750 attributes in BW 3.0+). 
Following by some other limitation that I published in by blog:
Here comes a doubt related to limit (if there is any) with regards of no of objects which are assigned to particular multiprovider. This goes along with performance. Actually which user runs a query against multiprovider OLAP processor is doing split of query to sub queries which every runs against particular infoprovider (e.g. base cube) which assigned into multiprovider. OLAP processor uses algorithm to run the sub queries. Depending on available systems work processes system runs them on certain amount of work processes in parallel. As a rule of thumb it is recommended to no go with more than 10 cubes per multiprovider. So in case you creating very patulous this can be bottleneck. 
For details see following SAP Notes:
629541 - Multiprovider: Parallel Processing
728017 - Multiprovider processing - exclusion of part providers

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