FW: Large IN LIST in an OBIEE query

From: Chitale, Hemant Krishnarao <Hemant.Chitale_at_sc.com>
Date: Mon, 31 Oct 2011 09:33:37 +0800
Message-ID: <8375C7FDC01FEB40A11B49DD940A96AB0110A4B5_at_HKJUMXMB110B.zone1.scb.net>

Mark, Michael, Jared, Stephane, Greg and others :

Thank you for all your responses.

Some background : (and answering Greg's questions "what is being done and where does this list come from ?") Apparently users run a prior query that retrieves a list of IDs (6000 odd). Then, they "paste" the IDs from an XLS sheet into OBIEE -- that is what was explained to me. The way the data model is designed, OBIEE runs 3 queries against 3 different FACT tables and then "stitches" the results together. Each query is run with a 1,000 entry IN LIST.

Currently, the "solution" I am recommending is to have these 6000 odd IDs being redirected to a "Temp" table and then join the Temp table in the query (or in all 3 queries).

Apparently, OBIEE has the concept of "Persist Connection Pool"
(11g documentation : http://download.oracle.com/docs/cd/E21764_01/bi.1111/e10540/conn_pool.htm#CHDJADFA

but this feature is supposed to be available in OBIEE 10g as well).
(My "solution" was before I discovered this feature from a ---- guess what ? --- Google search for "OBIEE IN LIST Performance").

Hemant K Chitale

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Chitale, Hemant Krishnarao Sent: Friday, October 28, 2011 4:50 PM
To: oracle-l_at_freelists.org
Subject: Large IN LIST in an OBIEE query

I have a few OBIEE queries that "perform poorly". Apparently, the users are allowed to "insert" a list of values to query for. OBIEE then constructs the query with a large IN LIST. If I move the IN LIST values into a temporary table and then join the temporary table, I get better performance. However, making this change in OBIEE requires a change to the OBIEE data model.

My questions :
a. Have you come across performance issues with very large IN LISTS (1000 entries)
b. If you raise a request to change the OBIEE data model, what is the level of resistance you face ? Are the OBIEE designers comfortable with making changes to add an interim table and join OR is this difficult ?   

Hemant K Chitale

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Received on Sun Oct 30 2011 - 20:33:37 CDT

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