LOB对象在数据泵导出、导入后查询对象数量发现丢失

2.1创建测试表（包含LOB字段）：

SQL> create table loba(id int,name clob) tablespace users;

 

2.1.2 查询用户信息：发现创建一个LOB字段的表：自动创建SYS命名的LOB index and LOB segments

SQL> select object_name,object_type,status from user_objects;

OBJECT_NAME                           OBJECT_TYPE         STATUS

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

LOBA                                      TABLE               VALID

SYS_IL0000089677C00002$$                  INDEX               VALID

SYS_LOB0000089677C00002$$                 LOB                 VALID

 

2.1.3查询视图：用户下LOB字段的相关信息

SQL> select TABLE_NAME,COLUMN_NAME,SEGMENT_NAME,TABLESPACE_NAME,INDEX_NAME from user_lobs;

TABLE    COLUMN      SEGMENT                  TABLESPACE_NAME    INDEX_NAME

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

LOBA    NAME  SYS_LOB0000089677C00002$$   USERS   SYS_IL0000089677C00002$$

 

2.1.4查询用户下的对象信息

SQL> select OBJECT_NAME,STATUS,object_id from user_objects;

SYS_IL0000089677C00002$$            VALID        89679

SYS_LOB0000089677C00002$$           VALID        89678

LOBA                                VALID        89677

 

2.2.1导出：
expdp  \‘/ as sysdba\‘ DIRECTORY=yang logfile=scott.log DUMPFILE=scott.dmp schemas=‘scott‘ CONTENT=METADATA_ONLY 

2.2.2dump文件传输
$ scp scott* 192.168.20.67:/home/oracle/.

2.2.3导入：
impdp \‘/ as sysdba\‘ directory=yang dumpfile=scott.dmp remap_schema=scott:song remap_tablespace=users:abc

2.2.4查询对比：
#对比发现：导入的表是新建的，JOB段也是新建，命名规则中使用了表的OBJECT_ID，因此导入的表，对象除了表明相同，JOB字段、索引都不同
select OBJECT_NAME,STATUS,object_id from user_objects;
OBJECT_NAME                        STATUS   OBJECT_ID
----------------------------------- ------- ----------
LOBA                             VALID        15471
SYS_IL0000015471C00002$$         VALID        15473
SYS_LOB0000015471C00002$$        VALID        15472

#查询对象类型，对象数量

SQL> select count(*),status,OBJECT_TYPE from user_objects group by status,object_type;
 COUNT(*) STATUS  OBJECT_TYPE
---------- ------- -------------------
         2 VALID   TABLE PARTITION
        14 VALID   TABLE
         1 VALID   SEQUENCE
         7 VALID   INDEX
         1 VALID   LOB

#源库drop LOB字段的测试表

SQL> drop table loba;

#从用户对象角度上，查询得到：LOB字段的表，drop 删除后，TABLE AND INDEX都删除了，LOB段保留且有效

SQL> select count(*),status,OBJECT_TYPE from user_objects group by status,object_type;
  COUNT(*) STATUS  OBJECT_TYPE
---------- ------- -------------------
         2 VALID   TABLE PARTITION
        13 VALID   TABLE
         1 VALID   SEQUENCE
         6 VALID   INDEX
         1 VALID   LOB
 
#查询用户下的LOB段
SQL> select object_name,OBJECT_TYPE,status from user_objects where object_type=‘LOB‘;
OBJECT_NAME                         OBJECT_TYPE         STATUS
----------------------------------- ------------------- -------
SYS_LOB0000089677C00002$$           LOB                 VALID

 
SQL> select * from cat;
BIN$aO6HsIdjTr3gU4AUqMDssg==$0 TABLE

#查询用户下的LOBS相关信息：
select TABLE_NAME,COLUMN_NAME,SEGMENT_NAME,TABLESPACE_NAME,INDEX_NAME from user_lobs;
NULL

SQL> create table loba(id int,name clob) tablespace users;

SQL> select TABLE_NAME,COLUMN_NAME,SEGMENT_NAME,TABLESPACE_NAME,INDEX_NAME from user_lobs;
TABLE    COLUMN      SEGMENT                  TABLESPACE_NAME    INDEX_NAME
------------------------------ ------------------------------
LOBA     NAME    SYS_LOB0000015553C00002$$      USERS  SYS_IL0000015553C00002$$

 
#查询LOB的表，LOB段，索引
SQL> select object_name,object_type,status from user_objects where object_name 
 in (‘LOBA‘,‘SYS_LOB0000015553C00002$$‘,‘SYS_IL0000015553C00002$$‘);
OBJECT_NAME                          OBJECT_TYPE         STATUS
-------------------------------------------------------------
LOBA                                  TABLE               VALID
SYS_IL0000015553C00002$$              INDEX               VALID
SYS_LOB0000015553C00002$$             LOB                 VALID


#DROP
SQL> drop table loba purge;


#再次查询：记录清除
SQL> select object_name,object_type,status from user_objects where object_name 
 in (‘LOBA‘,‘SYS_LOB0000015553C00002$$‘,‘SYS_IL0000015553C00002$$‘);
no rows selected


#查询用户下的LOB信息，也被删除
SQL> select * from user_lobs;
no rows selected