[20151126]IMPDP TRANSFORM参数.TXT

--最近要建立一个测试库，原来生产系统的一些表在定义时
STORAGE    (
            INITIAL          8G
            ....
           )
NOPARALLEL;

--实际我不需要建立这个大的INITIAL表，而且可能许多还是空的。有些我可能仅仅导入少量数据，这样要浪费大量磁盘空间，并且测试
--机器磁盘空间也不足。不能这样导入。

--另外一个问题有一些表我设置PCTFREE很大(缺省10)，主要问题是避免行迁移。如果这样导入也会导致磁盘空间浪费。

--这导致我开始想通过先建立空表，然后导入的想法，我仔细阅读参数TABLE_EXISTS_ACTION，参考链接
--http://blog.itpub.net/267265/viewspace-1846224/

--晚上我仔细看一些文档，发现oracle 11G还支持参数TRANSFORM,通过这个参数可以屏蔽原来的参数，还是通过例子来说明：

1.建立测试环境：

SCOTT@book> @ &r/ver1

PORT_STRING                    VERSION        BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

--建立如下表：
CREATE TABLE SCOTT.EMPX
(
  EMPNO     NUMBER(4),
  ENAME     VARCHAR2(10 BYTE),
  JOB       VARCHAR2(9 BYTE),
  MGR       NUMBER(4),
  HIREDATE  DATE,
  SAL       NUMBER(7,2),
  COMM      NUMBER(7,2),
  DEPTNO    NUMBER(2)
)
TABLESPACE USERS
RESULT_CACHE (MODE DEFAULT)
PCTUSED    0
PCTFREE    50
INITRANS   1
MAXTRANS   255
STORAGE    (
            INITIAL          50M
            NEXT             1M
            MAXSIZE          UNLIMITED
            MINEXTENTS       1
            MAXEXTENTS       UNLIMITED
            PCTINCREASE      0
            BUFFER_POOL      DEFAULT
            FLASH_CACHE      DEFAULT
            CELL_FLASH_CACHE DEFAULT
           )
NOPARALLEL;

SCOTT@book> insert into empx select * from emp ;
14 rows created.

SCOTT@book> commit ;
Commit complete.

--建立表empx，INITIAL=50M,PCTFREE=50.

SCOTT@book> select segment_name,bytes,blocks,INITIAL_EXTENT,NEXT_EXTENT from dba_segments where owner=user and segment_name='EMPX';
SEGMENT_NAME              BYTES     BLOCKS INITIAL_EXTENT NEXT_EXTENT
-------------------- ---------- ---------- -------------- -----------
EMPX                   52428800       6400       52428800     1048576

SCOTT@book> column PARTITION_NAME noprint
SCOTT@book> select * from dba_extents where owner=user and segment_name='EMPX';
OWNER  SEGMENT_NAME         SEGMENT_TYPE       TABLESPACE_NAME  EXTENT_ID    FILE_ID   BLOCK_ID      BYTES     BLOCKS RELATIVE_FNO
------ -------------------- ------------------ -------------------------- ---------- ---------- ---------- ---------- ------------
SCOTT  EMPX                 TABLE              USERS                    0          4       1280    8388608       1024            4
SCOTT  EMPX                 TABLE              USERS                    1          4       2304    8388608       1024            4
SCOTT  EMPX                 TABLE              USERS                    2          4       3328    8388608       1024            4
SCOTT  EMPX                 TABLE              USERS                    3          4       4352    8388608       1024            4
SCOTT  EMPX                 TABLE              USERS                    4          4       5376    8388608       1024            4
SCOTT  EMPX                 TABLE              USERS                    5          4       6400    8388608       1024            4
SCOTT  EMPX                 TABLE              USERS                    6          4       7424    1048576        128            4
SCOTT  EMPX                 TABLE              USERS                    7          4       7552    1048576        128            4
8 rows selected.

--可以看到分配6个8M的段，2个1M的段。这样占用很大的磁盘空间。

2.导出：
$ expdp scott/book  dumpfile=empx78.dmp logfile=empx78.log tables=scott.empx
Export: Release 11.2.0.4.0 - Production on Thu Nov 26 09:47:13 2015
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Starting "SCOTT"."SYS_EXPORT_TABLE_01":  scott/a******* dumpfile=empx78.dmp logfile=empx78.log tables=scott.empx
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 50 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "SCOTT"."EMPX"                              8.562 KB      14 rows
Master table "SCOTT"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SCOTT.SYS_EXPORT_TABLE_01 is:
  /u01/app/oracle/admin/book/dpdump/empx78.dmp
Job "SCOTT"."SYS_EXPORT_TABLE_01" successfully completed at Thu Nov 26 09:47:28 2015 elapsed 0 00:00:11

3.如果按照原来导入，占用50M太浪费：

Usage: TRANSFORM = transform_name:value[:object_type]
These are the applicable transform_names

SEGMENT_ATTRIBUTES: by default value is y which will copy the objects as it is in the export dump with all segment
    attributes. If you specify the value as n the import job will omit the segment_attributes in the dump file and it
    will use the tablespace/user default values.

STORAGE: by default the value for this parameter is y which will include all storage clauses during the import job.
    If you specify the parameter value as n then it will omit the storage clause in the dump file and it will follow the
    default values in the tablespace.

PCTSPACE: it is the percent multiplier for the extent allocations and size of the datafiles during the import.

OID: object id (OID) mainly used for the TYPE objects. Each and every type is identified by OID which will be
    unique. If you create a type without specifying the OID the RDBMS itself will create and assign unique OID to the
    new TYPE object. See below examples for more details.

$ impdp scott/book dumpfile=empx78.dmp logfile=empx78x.log remap_table=scott.empx:empy full=y transform=SEGMENT_ATTRIBUTES:n:table,STORAGE:N:table
Import: Release 11.2.0.4.0 - Production on Thu Nov 26 09:53:46 2015
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SCOTT"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
Starting "SCOTT"."SYS_IMPORT_FULL_01":  scott/a***** dumpfile=empx78.dmp logfile=empx78x.log remap_table=scott.empx:empy full=y transform=SEGMENT_ATTRIBUTES:n:table,STORAGE:N:table
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "SCOTT"."EMPY"                              8.562 KB      14 rows
Job "SCOTT"."SYS_IMPORT_FULL_01" successfully completed at Thu Nov 26 09:53:51 2015 elapsed 0 00:00:03

SCOTT@book> @ &r/ddl scott.empy
C100
---------------------------------------------------------------------------------
  CREATE TABLE "SCOTT"."EMPY"
   (    "EMPNO" NUMBER(4,0),
        "ENAME" VARCHAR2(10),
        "JOB" VARCHAR2(9),
        "MGR" NUMBER(4,0),
        "HIREDATE" DATE,
        "SAL" NUMBER(7,2),
        "COMM" NUMBER(7,2),
        "DEPTNO" NUMBER(2,0)
   ) SEGMENT CREATION IMMEDIATE
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
NOCOMPRESS LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "USERS" ;

--注意看INITIAL=64k,PCTFREE=10.

SCOTT@book> select * from dba_extents where owner=user and segment_name='EMPY';
OWNER  SEGMENT_NAME         SEGMENT_TYPE       TABLESPACE_NAME                 EXTENT_ID    FILE_ID   BLOCK_ID      BYTES     BLOCKS RELATIVE_FNO
------ -------------------- ------------------ ------------------------------ ---------- ---------- ---------- ---------- ---------- ------------
SCOTT  EMPY                 TABLE              USERS                                   0          4        744      65536          8            4

--这样就符合我的需要了。我还可以先导入表定义，这样再通过其它的方式插入数据。使用参数CONTENT=METADATA_ONLY。
--例子：

$ impdp scott/book dumpfile=empx78.dmp logfile=empx78x.log remap_table=scott.empx:empz full=y transform=SEGMENT_ATTRIBUTES:n:table,STORAGE:N:table CONTENT=METADATA_ONLY
Import: Release 11.2.0.4.0 - Production on Thu Nov 26 09:58:50 2015
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SCOTT"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
Starting "SCOTT"."SYS_IMPORT_FULL_01":  scott/a******* dumpfile=empx78.dmp logfile=empx78x.log remap_table=scott.empx:empz full=y transform=SEGMENT_ATTRIBUTES:n:table,STORAGE:N:table CONTENT=METADATA_ONLY
Processing object type TABLE_EXPORT/TABLE/TABLE
Job "SCOTT"."SYS_IMPORT_FULL_01" successfully completed at Thu Nov 26 09:58:54 2015 elapsed 0 00:00:02

SCOTT@book> select * from dba_extents where owner=user and segment_name='EMPZ';
no rows selected

--如果不指定后面的参数:table，改成如下SEGMENT_ATTRIBUTES:n, 对其它object_type也有效。