oracle desc dba_data_files視圖報ORA-4043錯誤小記

今天在做測試的時候想查詢資料檔案對應的資料表空間資訊，desc dba_Data_files視圖時發現報不存在這個對象。當時以為自己的DB在mount下沒法查詢是正常的，後來在DB OPEN下查詢 dba_data_files還是報不存在這個對象。頓時感覺疑惑了，其他對象都查詢正常，唯獨DBA_*的視圖都不能正常查詢使用。查詢MOS（文檔 ID 296235.1） 發現如下描述：

APPLIES TO:
 Oracle Database - Enterprise Edition - Version 8.1.7.4 to 11.2.0.1 [Release 8.1.7 to 11.2]
 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.

正是由於我在資料庫mount狀態下查詢dba_data_files視圖，導致遭遇oracle 資料庫產品的Bug 2365821，資料庫即使OPEN下也不能正常使用dba_*視圖。

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