Skip to Content

AGGREGATES:

Ø  Aggregates are the smaller cubes which are built on  cube in order  to improve the query performance

Ø  Aggregates are specific to the characteristic , but by default it will take all the key figures of the cube

Ø  When we execute a query the processer will search for suitable aggregate, if it founds it fetches data from the aggregate, if not it search for data in the cube

Ø  Thumb Rule: DB is > 30% of the total time & Aggregation ratio should be > 10%

Ø  Select the info cube à Context menu à Maintain Aggregates à Create by yourself à Create à Specify description à OK à Drag & Drop the characteristic to right side on which you want aggregate à Activate à Continue à Now à

Ø  Observe the F table & E table for aggregate

Ø  Select aggregate à Click on Display Aggregate data

Ø  Initial fill: After creation of  the Aggregate whatever the data we load for first time from cube to Aggregate is called Initial Fill

Ø  Roll Up: After the Initial fill, what related data that has been loaded to cube has rolled back to the aggregates, this can be performed process called Roll Up. If you don’t do the roll up , this request will not be available for reporting

Ø  Go to Info Cube Manage à Roll up Tab à Selection à Immediate à Execute

Ø  Aggregates degrades the Database Performance

Ø  If we have more aggregates, it degrades the Performance of ‘Attribute Change Run’

Ø  Aggregates by default set to compression  & we cannot built a query on aggregates

Ø  Whenever we run the query, how can we know the data is fetching from Aggregate or from cube?

Ø  RSRT àSpecify the query name à Execute + Debug à Select Display Aggregate found à OK

Ø  Technical name of the Aggregate formed by the system after activation

Ø  We can have multiple aggregates built on a single cube

Ø  Different flexibilities:

Ø  Maintain aggregate selectively for characteristic à Select the characteristic à Context menu à Fixed value à Select the value as per requirement à Ok à Activate  

Ø  Navigational attribute can be used in building aggregates. Create a navigational attribute for characteristic à Aggregate maintenance à Drag & Drop navigational attributeà select the aggregate & save à Activate & refill

Ø  Based on the customer number, navigational attribute value will get assigned

Ø  Property of Aggregate additive, Property of master data overwrites

Ø  Whenever we change master data, data in the aggregated need to be changed as per attribute table, to reflect those changes we run“ Attribute Change Run”

Ø  RSA1 àTools Menu à Apply Hierarchy / Hierarchy Attribute change run à Selection Option (Immediate) à Info Object list (main Char) à Save à Back à Execute

Ø  We can use Hierarchies while building aggregatesàSelect the CNO à Context Menu à Hierarchy Level à Node Level (03) à Select aggregate & Save à Activate & Refill

Ø  Maintaining aggregate with multiple selective characteristics is not possible à To overcome with this problem we have to build multiple aggregates

Ø  Different Options with Aggregates: Switch on/off,  When we switch off an Aggregate, the structure of aggregate will be in present but the aggregate will not identified by OLAP Processer for reporting

Ø  Whenever we required we can switch on

Ø  Deactivate: Structure of aggregated will be there, but data will get deleted

Ø  OLAP TIME: Query Design, Modelling Aspects, OLAP Cache, Compression, Aggregates

Ø  Frontend Time: Query Design, Modelling Aspects, Formatting

To report this post you need to login first.

Be the first to leave a comment

You must be Logged on to comment or reply to a post.

Leave a Reply