InfoCube Compression

1.COMPRESSIONS :

if i compress the info cube it aggregated the key figre values with same char combinations

ic
r1----eid/pid////sales
        100/11/1000
      200/12/1200 

r2---eid/pid/sales
      300/11/1200
      100/11/1200


q1----emp sale---db read----4 records///olap aggreagtion---2 records

100/11/2200
200/12/1200
300/11/1200

q1--eid/sales----db reocrds---3///////olap---0--------Reducing db read time/////Olap aggregation time---query performance

before compression data is there in "F" fact table//////after compression data is moved to "E" fact table

ic1----------req1/2/3/4/5-----compress--req5----sys compresses older request also---forms a unique request---00--ther in e fact table


after compression we cant delet data request wise----
ods---to info cube---compression


ods---icube--compress

ods
docno/eid/sales
1/100/1000

--activate=------100/1000-------------------info cube----100/1000

1/100/1500

ods
adt--1500

clt
-1000
1500

ods to infocube
-1000+1500=500

100///1000
100//500----------compress-----------100/1500


reconstruction--reinsert the delted data from info cube-----

1.psa must hold the data
2.status of the trnsafer stru must not be changed
3.update rules of the infocube--must be active


Selctive deletion:req--1---all the data is delted=-------if i want to delete the records selctively we have to go for selective deltion

req1-----eid 100

req1/2/3------------------100