Showing posts with label Aggregates. Show all posts
Showing posts with label Aggregates. Show all posts

Friday 26 April 2013

Disadvantages of AGGREGATES, COMPRESSION, IC PARTIONING, INDEXES, LINE ITEM DIMENSIONS

Disadvantages of 

(1) AGGREGATES

Even though Aggregates are used for performance, but it will decrease the same when you create more aggregates. 
Until Rollup takes place the query won't hit the aggregate Cube
Aggregates - its main disadvantage is that it stores data physically as a redundant, more aggregates will cause waste of memory.

(2) COMPRESSION

Once Cube is compressed, then all the request number will be removed and hence deletion by request id is no more possible.
Compression- compressed request cannot be got back to normal, deletion is difficult

(3) Partition

Partition Handling for several thousand partitions is usually impacting DB performance.
IC partition  - partition cannot be done after data loaded (3.X) but repartition is possible in BI 7.0

(4) INDEXES

If you don't drop the index before loading then the data load will be slow
If you don't create the index before the reporting then the reporting will be slow
Index- for large volume of data create and delete index consume lot of time

(5) LINE ITEM DIMENSIONS

This can be set when you have one only characteristic in the Dim table.
Line item - more number of line item cannot be used as number char used will be reduced.