Performance issue due to column formula and filters

Question

Hi,
I am facing strange issue with performance for my OBIEE reports. I have two sets of reports Static and Dynamic. Both runs against same tables. The only difference between these reports is that the Static reports would run against all the data for given aggregation level e.g. Year, Month, Date and so on. Where as for Dynamic one I have range prompts to filter data. Other difference is that I have a column formula for one of the column in the Dynamic report, which is nothing but Go URL to show another page with certain parameters.
The static report takes around 14-15 Seconds where as the Dynamic one takes around 3.5 min. The amount of data and range is same here. From the logs I could see that for the Static reports, i.e. reports without filters it applys group by at SQL level where as it is not doing so for the dynamic one. Is this expected ?
Second issue is, even if I say remove the filters and just have report with column formula in one and no formula in other there is significant time difference in the processing at Presentation service layer. Again this is taken from the log. it takes 8 second to get data from DB but shows almost 218 Seconds as response time at Presentation layer.
Below are conceptual details about table and reports -
Table 1 (It is date dimension) : Date_Dim
DateCode Date
Day Number
MonthCode Varchar2
YearCode Varchar2
Table 2 (It is aggregate table at year level) : Year_Aggr
DateCode Date (FK to Table1 above)
Measure1
Measure2
Measure3
Measure4
Measure5
Report 1
Date_Dim.YearCode | Year_Aggr.Measure1 | Year_Aggr.Measure2 | Year_Aggr.Measure3 | Year_Aggr.Measure4
Report 2
Dashboard Filter : Dimension1 | Dimension2 | Year Start | Year End |
Date_Dim.YearCode | Year_Aggr.Measure1 | Year_Aggr.Measure2 | Year_Aggr.Measure3 | Year_Aggr.Measure4
Column formula for Date_Dim.YearCode is something like :
'<a href="saw.dll?Dashboard&PortalPath=somepath and parameters  target=_self>'  || Date Dim"."YearCode" || '</a">'
Filters :
Dimension1 is prompted...
Dimension2 is prompted...
cast("Date Dim"."YearCode" as Int) is greater than or equal to @{Start_Year}
cast("Date Dim"."YearCode" as Int) is greater than or equal to @{End_Year}
Note : I need to apply cast to int as column is varchar2, legacy problem.+
How can I fix this? Am I missing something? In the result of report2 the DB SQL doesn't show the year in where thought it is displayed in the logical sql.
Let me know if anybody had faced this and have fixed. Or suggetion to make changes to fix this.
Thannks,
Ritesh</a>

Answer 1

Hi Ritesh,
I think you right about the root cause of your problem. The first request does the group by in the database which returns fewer records to the BI Server for processing. The second request does not do the group by and sends significantly more records back to the BI server forcing it to do the group by. Compound that with the fact that pivot table views are relatively expensive computationally and that explains the difference between the execution times.
Assuming that the execution time of the first report is satisfactory, I would recommend you try to experiment with a few settings to see if you can get the second report to do the group by in the database.
Are the two filters identical except for the following conditions?
cast("Date Dim"."YearCode" as Int) is greater than or equal to @{Start_Year}
cast("Date Dim"."YearCode" as Int) is greater than or equal to @{End_Year}
Best regards,
-Joe