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RE: Index-Organized Table experiences

From: Goulet, Dick <DGoulet_at_vicr.com>
Date: Wed, 28 Apr 2004 10:48:18 -0400
Message-ID: <4001DEAF7DF9BD498B58B45051FBEA656D8462@25exch1.vicorpower.vicr.com>


Daniel,

        I've had IOT's around in production since 8.0.5 just for the very = reason you are looking at. We have some lookup type tables that have = two to three columns and all of the columns form the primary key. In = older versions of Oracle you'd have to have a table and a separate = index, except that the table never gets used. Therefore the IOT is the = perfect replacement, table and index in one. The only bad, that's been = fixed in 8i was that you could not add a column to an IOT. Now in 9i = they've added the ability to have multiple indexes on an IOT if needed, = haven't found a reason for that, yet.

Dick Goulet
Senior Oracle DBA
Oracle Certified 8i DBA

-----Original Message-----

From: Daniel Fink [mailto:Daniel.Fink_at_Sun.COM] Sent: Wednesday, April 28, 2004 10:15 AM To: oracle-l_at_freelists.org
Subject: Index-Organized Table experiences

We are looking to implement IOTs for a couple of intersection entities in a 10g db. I would like to hear from those brave enough to actually use IOTs what is the good, the bad and the ugly.=20

example:

Employee (heap table)
Project (heap table)

There is a many-to-many relationship between the tables (1 employee can be on many projects and 1 project can have many employees).

The emp_project table is the intersection entity containing emp_id and project_id as the only columns. There are FK constraints on each of the columns. The combination of emp_id and project_id is unique.

This situation *sounds* like the right one for an IOT, otherwise we would have 1 table and 2 indexes (1 on each column).

My main concerns are:
1) Integrity/performance
2) Locking behavior (do I need to adhere to the traditional "index all foreign keys" rule to prevent excessive locking?) 3) Any especially nasty gotchas

Thanks,
Daniel



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Received on Wed Apr 28 2004 - 09:47:01 CDT

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