OBIEE generates complex queries

Question

Hi,
Currently we are experiencing performance issues, i.e. some queries are running for a very long time. I examined these queries and it struck me that it could be caused by the complexity of the generated queries. For example, a query accessing only one facttable accessed that facttable 5 times (the queries are concatenated through the WITH statement) ! I wonder, why is this necessary? Business Objects XI does not generate such complex queries, BO XI would access that facttable only one time.
Basically my question is: which settings affect the queries generated by OBIEE? Isn't it possible to generate different, simpler queries?
TIA,
EriK

Answer 1

Thanks guys. Bad design could be a reason.. but we're using Oracle's own product called BI-APPS and I expect that to be perfect...:-)
Here is an example of a query that is imho way too complex:
WITH
SAWITH0 AS (select sum(T258218.LINE_AMT * T258218.GLOBAL1_EXCHANGE_RATE) as c1,
T551303.PROJECT_NUMBER as c2,
T258218.PURCH_ORDER_NUM as c3
from
W_PROJECT_D T551303 /* Dim_W_PROJECT_D_Project */ ,
W_PURCH_COST_F T258218 /* Fact_W_PURCH_COST_F */
where ( T258218.DELETE_FLG = 'N' and T258218.PROJECT_WID = T551303.ROW_WID and T551303.PROJECT_NUMBER = '101491' )
group by T258218.PURCH_ORDER_NUM, T551303.PROJECT_NUMBER),
SAWITH1 AS (select distinct SAWITH0.c2 as c1,
SAWITH0.c3 as c2,
SAWITH0.c1 as c3,
SAWITH0.c1 as c4,
SAWITH0.c1 as c5
from
SAWITH0),
SAWITH2 AS (select distinct SAWITH1.c1 as c1,
SAWITH1.c2 as c2,
SAWITH1.c3 as c3
from
SAWITH1),
SAWITH3 AS (select sum(T258218.LINE_AMT * T258218.GLOBAL1_EXCHANGE_RATE) as c1,
T551303.PROJECT_NUMBER as c2,
T258218.PURCH_ORDER_NUM as c3
from
W_PROJECT_D T551303 /* Dim_W_PROJECT_D_Project */ ,
W_PURCH_COST_F T258218 /* Fact_W_PURCH_COST_F */
where ( T258218.DELETE_FLG = 'N' and T258218.PROJECT_WID = T551303.ROW_WID and T551303.PROJECT_NUMBER = '101491' )
group by T258218.PURCH_ORDER_NUM, T551303.PROJECT_NUMBER),
SAWITH4 AS (select distinct SAWITH3.c2 as c1,
SAWITH3.c3 as c2,
SAWITH3.c1 as c3,
SAWITH3.c1 as c4,
SAWITH3.c1 as c5
from
SAWITH3),
SAWITH5 AS (select sum(SAWITH4.c4) as c4,
SAWITH4.c1 as c5
from
SAWITH4
group by SAWITH4.c1),
SAWITH6 AS (select sum(T258218.LINE_AMT * T258218.GLOBAL1_EXCHANGE_RATE) as c1,
T551303.PROJECT_NUMBER as c2,
T258218.PURCH_ORDER_NUM as c3
from
W_PROJECT_D T551303 /* Dim_W_PROJECT_D_Project */ ,
W_PURCH_COST_F T258218 /* Fact_W_PURCH_COST_F */
where ( T258218.DELETE_FLG = 'N' and T258218.PROJECT_WID = T551303.ROW_WID and T551303.PROJECT_NUMBER = '101491' )
group by T258218.PURCH_ORDER_NUM, T551303.PROJECT_NUMBER),
SAWITH7 AS (select distinct SAWITH6.c2 as c1,
SAWITH6.c3 as c2,
SAWITH6.c1 as c3,
SAWITH6.c1 as c4,
SAWITH6.c1 as c5
from
SAWITH6),
SAWITH8 AS (select sum(SAWITH7.c5) as c3
from
SAWITH7)
select SAWITH2.c1 as c1,
SAWITH2.c2 as c2,
SAWITH2.c3 as c3,
SAWITH5.c4 as c4,
SAWITH8.c3 as c5
from
SAWITH2,
SAWITH5,
SAWITH8
where ( nvl(SAWITH2.c1 , 'q') = nvl(SAWITH5.c5 , 'q') and nvl(SAWITH2.c1 , 'z') = nvl(SAWITH5.c5 , 'z') )
Basically the query is:
select sum(T258218.LINE_AMT * T258218.GLOBAL1_EXCHANGE_RATE) as c1,
T551303.PROJECT_NUMBER as c2,
T258218.PURCH_ORDER_NUM as c3
from
W_PROJECT_D T551303 /* Dim_W_PROJECT_D_Project */ ,
W_PURCH_COST_F T258218 /* Fact_W_PURCH_COST_F */
where ( T258218.DELETE_FLG = 'N' and T258218.PROJECT_WID = T551303.ROW_WID and T551303.PROJECT_NUMBER = '101491' )
group by T258218.PURCH_ORDER_NUM, T551303.PROJECT_NUMBER
but this query is repeated multiple times. It looks like a self join - but why is OBIEE generating such a complex query? And can it be affected?
Edited by: user10984315 on 18-Mar-2011 08:29
Edited by: user10984315 on 18-Mar-2011 08:30