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How to Cleanup and Rebuild an Interrupted Online Index Rebuild - ORA-8104 , ORA-8106 (Doc ID 272735.1)

Last updated on JULY 05, 2023

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 11.2]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.



Sometimes an online rebuild of an index reports an ORA-8104.
There can be many reasons for that.

For instance in a highly active database with many transactions the likelyhood of uncommitted transactions on a table is high. So if such a table needs to rebuild an index we may see this error
due to uncommitted transactions. In other cases we may see a dead process with an uncommitted transaction holding a lock on the table. This also prevents us from rebuilding the index. This is
all by design of the online rebuild functionality. However, we can't leave a database in this state forever so SMON has been designed to cleanup these cases.

A process could end up dead if it has been killed from the OS with the command kill -9.

If the process was killed while doing an:
then the index could end up in a state where it needs clearing up.

One would think a drop of the index would solve the problem. However,
that will only return an error:ORA-8104 "This index object %s is being online built or rebuilt."


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