corrupted index in system tablespace

I have corrupted index in system tablespace:
Index Name:         I_OBJ1
Table Name:         OBJ$
Owner:                 SYS
Tablespace:          SYSTEM
How do I rebuild this index and waht are the potensial problems?
The corruption was found through trace file.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Mark GeerlingsDatabase AdministratorCommented:
Start with taking a backup that you can restore that if necessary, to at least get back to where things are now.

If you've been taking backups regulary and are running in archivelog mode, you could consider restoring an older backup and running through the archived redo logs up to the point in time when the corruption occured (if you can determine when that was).

Do a complete export.  That should give you everything you need to rebuild your database completely, and you may have to do that.

I'm sure you know that Oracle usually does not support users or DBA directly changing objects in the SYS schema (the SYS.AUD$ table is an exception - you can truncate or delete rows from that table).  Have you contacted Oracle support for their help on this?

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
johnsoneSenior Oracle DBACommented:
As this is an index, I would think you should be able to rebuild it.  I would do it in restricted mode with no users on the database.

You would definitely want an opinion from Oracle though.  They may consider your database unsupported if you do that.

The easiest way, run this script:


this will recompile all the invalid and corrupted objects.
Big Business Goals? Which KPIs Will Help You

The most successful MSPs rely on metrics – known as key performance indicators (KPIs) – for making informed decisions that help their businesses thrive, rather than just survive. This eBook provides an overview of the most important KPIs used by top MSPs.

Mark GeerlingsDatabase AdministratorCommented:
To seazodiak,

That suggestion will not help.  Here is the documentation from the top of the "utlrp.sql" file:
Rem $Header: utlrp.sql 15-nov-2001.10:56:31 rburns Exp $
Rem utlrp.sql
Rem Copyright (c) 1998, 2001, Oracle Corporation.  All rights reserved.  
Rem    NAME
Rem      utlrp.sql - UTiLity script Recompile invalid Pl/sql modules
Rem     This is a fairly general script that can be used at any time to
Rem     recompile all existing invalid PL/SQL modules in a database.
-- (end of clip from file)

Note that it only re-compiles PL\SQL objects.  It does not rebuild indexes that have problems.

To harlemit:

Your best option is to contact Oracle technical support and follow their recommendations.  If that is not an option for you (like if you are running an Oracle database without paying for support) then you are unsupported anyway, so login as SYS and drop, then recreate that index.

Of course, before doing that, make a complete backup and if possible a complete export, so if dropping and rebuilding this index creates more problems, you can go back to where you are now.

I guess it's true by saying "nothing is what it seems" ;-)

though what you said is absolutely correct, but UTLRP.sql do a lot more than pl/sql recompilation.
it recompiles all the invalid objects instead.

Here is the evidence:

In the Header comments of UTLRP.SQL : REad the last line

Rem    NAME
Rem      utlrp.sql - UTiLity script Recompile invalid Pl/sql modules
Rem     This is a fairly general script that can be used at any time to
Rem     recompile all existing invalid PL/SQL modules in a database.
Rem     If run as one of the last steps during migration/upgrade/downgrade
Rem     (see the README notes for your current release and the Oracle
Rem     Migration book), this script  will validate all PL/SQL modules
Rem     (procedures, functions, packages, triggers, types, views, libraries)


Now the story does not end here. if you look the contents below of this script, it will actually call another script:


In the header of this file:
Rem     This script provides a packaged interface to recompile all
Rem     existing invalid PL/SQL modules, Java classes, indextypes and
Rem     operators in a database sequentially or in parallel.

again look at  the last line, it even recompile the JAVA CLASS , not to mentiion the index types.

I don't remember when, but I remembered
that Once I recompiled by invoking that script to recompile the invalid indexes in the database dictionary catalogs.

but I guess the poster's situation might be different.

I am not sure the word "corrupted" is the block corrupted physically or logically.

In the former case, he might need to rebuild the block or recover from the backup.

in the latter, he might be able to rebuild it manually.
Obviously the only option will be to recover using a backup file. A sys object should not be rebuilt as this will lead to other problems.  Markgeer's answer seems to be the best solution
Do a FULL export.
After that do import (only on SYS schema, I am not sure if it is possible, if not - do a full import).
But use
parameter and use also logfile parameter.
In the logfile you will have an section for creating indexes. Filter using text editor the name of the index and the creation statement. After that drop the index and recreate it using that script.
johnsoneSenior Oracle DBACommented:
I believe markgeer is pointing out that utlrp will not rebuild a corrupted index.  In fact, I would not be surprised if the status on the index was still VALID.

What is being described sounds like block corruption in an index.

If you don't have support, rebuild the index.  If you do, I would contact Oracle for their recommendation.

I don't see a need to rebuild a database for a corrupted index.  If this was user data and not dictionary, we would all just rebuild the index, not restore a backup.
From SQL(DML) Level, You cannot rebuild OBJ$ about indexes, Even if you startup migrate/upgrade.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Oracle Database

From novice to tech pro — start learning today.