Bug 2365821，mount阶段desc dba_*导致open之后无法查询
今天用10g遇到这个问题，记录一下，这个问题甚至影响到了11.2.0.1版本。

ORA-4043 On DBA_* Views If They Are Described In Mount Stage (Doc ID 296235.1)

In this Document

APPLIES TO:

Oracle Database - Enterprise Edition - Version 8.1.7.4 to 11.2.0.1 [Release 8.1.7 to 11.2]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata 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.

SYMPTOMS

If you describe any DBA_* Views (Data dictionary views) in a mount stage, than you will not be able to 
 describe those views even after opening the database.

You can test as follows:

+ Shutdown the database.

SQL> Shutdown immediate

+ Mount the database.

SQL> Startup Mount

+ Describe any Data Dictionary view.

SQL> DESC DBA_DATA_FILES

ERROR:
ORA-04043: object DBA_DATA_FILES does not exist.

+ Open the Database.

SQL> ALTER DATABASE OPEN;

Database altered

+ Describe the same Data Dictionary view.

SQL> DESC DBA_DATA_FILES

ERROR:
ORA-04043: object DBA_DATA_FILES does not exist

*** Error will appear till we bounce the Database / flush the shared pool.

CAUSE

This is related to Bug 2365821

Abstract: ORA-4043 ON DBA_* TABLES IF THEY ARE DESCRIBED IN A MOUNT STAGE.

SOLUTION

Available workarounds are:

1) Don't describe the dba_* views at mount stage.

OR

2) If you issue DESC of any DBA_*views at mount stage, then shutdown and restart the DB instance.

OR

3) Flush the shared pool.

SQL> Alter system flush shared_pool;

and then reissue the failing command.