QT_*BUFFER Views Invalid after Downgrade from Oracle Database 12.1 (12c) (Doc ID 1520209.1)

Last updated on JULY 13, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.1 and later
Oracle Database - Standard Edition - Version 12.1.0.1 and later
Information in this document applies to any platform.
An important note is that when downgrading a database instance from the current version to the version prior to the upgrade, the database IS NOT returned to the same state as it was pre-upgrade.
Depending on the versions involved, the upgrade process makes changes that are not reversible.
The downgrade process allows users to open and access the database instance in the previous version. This is usually sufficient.

Additional, corrective actions (such as de-install / re-install or re-upgrade to current patchset levels) may be needed to settle left-over issues after a downgrade.
If the goal is to have the instance back EXACTLY as it was pre-upgrade then other processes including a recovery to just before the upgrade should be used.

Symptoms

After downgrading from a successful 12C upgrade to either 11.1 or 11.2, there can be one or more QT_*BUFFER Views Invalid.

The object number can change between versions or within the same version.  There is usually only one.

Examples of invalids are:

11.1:

There are 1 Invalid objects

OWNER        OBJECT_NAME                              OBJECT_TYPE

------------ ---------------------------------------- ----------------------------------------

SYS          QT103707_BUFFER                          VIEW

1 row selected.

 

11.2:

There are 1 Invalid objects

OWNER        OBJECT_NAME                              OBJECT_TYPE

------------ ---------------------------------------- ----------------------------------------

SYS          QT105853_BUFFER                          VIEW

1 row selected.

Changes

 QT_*BUFFER Views made invalid as part of a 12c> Downgrade process

Cause

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