Incorrect Usage of timestamp function cause DB to ignore indexed column.

Question

Hi
We upgraded the OBIEE version from version 10.1.3.2.1 to version 10.1.3.4.0. we have a column with type timestamp ( the column characteristics were not changed during the upgrade) and this column is indexed in the database.
In the old version when querying the database the BI used the function to_date which used the index of the column. In the new version the BI uses the function TIMESTAMP which doesn't use the index and thus causes severe performance problems.
I use dynamic repository variable that holds the last value of the column
Here are the 2 identical queries the produced in both versions version and the initialization block of the variable:
Query 1 - version 10.1.3.2.1:
select T41101.ORDER_NUMBER as c1,
sum(T41101.USD_LINE_TOTAL) as c2,
sum(T41101.CURRENCY_LINE_TOTAL) as c3
from
DWH_FACT_SO_WSH T41101
where ( T41101.SNAPSHOT_DATE_TIME = TO_DATE('2009-06-11 06:50:25' , 'YYYY-MM-DD HH24:MI:SS') )
group by T41101.ORDER_NUMBER
order by c1
Query 2 version 10.1.3.4.0:
select T41101.ORDER_NUMBER as c1,
sum(T41101.USD_LINE_TOTAL) as c2,
sum(T41101.CURRENCY_LINE_TOTAL) as c3
from
DWH_FACT_SO_WSH T41101
where ( T41101.SNAPSHOT_DATE_TIME = TIMESTAMP '2009-07-26 06:37:47' )
group by T41101.ORDER_NUMBER
order by c1
The initialization block of the Last_Snapshot_Time variable:
select snapshot_date_time from dwh_d_last_snapshot_details
which in both cases the data type of snapshot_date_time is timestamp.

Answer 1

Hi.
The database is Oracle?
What is the datatype of SNAPSHOT_DATE_TIME column in database, DATE or TIMESTAMP?
What is the datatype of SNAPSHOT_DATE_TIME column in the physical layer in the repository?
This happens only for default date prompt value (repository variable) or after you set value also?
What is the filter in Answers, SNAPSHOT_DATE_TIME is prompted?
Maybe you can write manually filter like SNAPSHOT_DATE_TIME = TO_DATE(@{p_v} , 'YYYY-MM-DD HH24:MI:SS') if p_v is TIMESTAMP or DATE (default from initialization block and from drop-down list or calendar).
Try.
Regards
Goran
http://108obiee.blogspot.com