Pass IR Filters to Interactive Report

Question

I am calling my Interactive Reports from a menu with IR filters ('SCHOOL' and 'YEAR') being passed to the report. I'm wondering if the interactive report queries all the data first and then applies the IR filters (which would be a performance problem). I ran the report in debug, but I'm not really sure how it evaluates the SQL. Does anybody know how passing IR filters to report work in the execution of the SQL?
select
null as apxws_row_pk,
"ATTENDANCE_CODE",
"ATTENDANCE_CODE_DESC",
"PK_ID",
count(*) over () as apxws_row_cnt
from (
select * from (
select A.PK_ID as "PK_ID",
A.YEAR as "FK_YEAR",
A.FK_SCHOOL as "FK_SCHOOL",
A.ATTENDANCE_CODE as "ATTENDANCE_CODE",
A.ATTENDANCE_CODE_DESC as "ATTENDANCE_CODE_DESC",
C.SCHOOL_YEAR as "YEAR"
from "#OWNER#"."SCHOOL_YEAR" C,
"#OWNER#"."SCH_BASE" B,
"#OWNER#"."ATTENDANCE_CODE" A
where B.PK_ID = A.FK_SCHOOL
and C.PK_ID = A.YEAR
) r
where ("SCHOOL" = :APXWS_EXPR_1
and "YEAR" = to_number(:APXWS_EXPR_2))
) r where rownum <= to_number(:APXWS_MAX_ROW_CNT)
order by "ATTENDANCE_CODE"

Answer 1

Stew
The information was not specific to rewrite, I was merely trying to show how tracing could be enabled to determine what the optimizer is doing (which was appropriate to the rewrite question). It will also show you the query actually being performed and the execution plan.
This information would allow you to see the query being passed to oracle by Apex and what predicates are in the query passed, which would go some way to answering the original question.
To your question a'n oracle SQL query is an oracle SQL query' - I'm not quite sure what you mean. Two differently constructed queries over the same tables, returning the same results can differ wildly in performance. Understanding the optimizer and the decisions it makes will change the way in which you write queries.
I've generally found out that the best way to determine what happens behind the scenes is to have a look. Getting information from the experts is fantastic, but working it out yourself or even just testing to confirm the answers you are given helps understanding even more.
Ben
Looking at the rownum clause, it will speed up the query if the ORDER BY clause is removed. If you are ordering the results, the entire result set must be returned first in order to get the first x rows. Without ordering, this is required.
Edited by: Munky on Jan 16, 2009 3:51 PM