导入导出 Oracle 分区表数据

--****************************

-- 导入导出 Oracle 分区表数据

--****************************

   

    导入导入Oracle 分区表数据是Oracle DBA 经常完成的任务之一。分区表的导入导出同样普通表的导入导出方式，只不过导入导出需要考

虑到分区的特殊性，如分区索引，将分区迁移到普通表，或使用原始分区表导入到新的分区表。下面将描述使用imp/exp，impdp/expdp导入导出

分区表数据。

 

    有关分区表的特性请参考： 

        Oracle 分区表

        SQL server 2005 切换分区表

        SQL server 2005 基于已存在的表创建分区

 

    有关导入导出工具请参考：

        数据泵EXPDP 导出工具的使用

        数据泵IMPDP 导入工具的使用

 

    有关导入导出的官方文档请参考：

        Original Export and Import     

 

一、分区级别的导入导出

    可以导出一个或多个分区，也可以导出所有分区(即整个表)。

    可以导入所有分区(即整个表)，一个或多个分区以及子分区。

    对于已经存在数据的表，使用imp导入时需要使用参数IGNORE=y，而使用impdp，加table_exists_action=append | replace 参数。

 

二、创建演示环境

    1.查看当前数据库的版本

        SQL> select * from v$version where rownum < 2;

 

        BANNER

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

        Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

 

    2.创建一个分区表

        SQL> alter session set nls_date_format='yyyy-mm-dd';

 

        SQL> CREATE TABLE tb_pt (

        sal_date   DATE NOT NULL,

        sal_id NUMBER NOT NULL,

        sal_row    NUMBER(12) NOT NULL)

        partition by range(sal_date)

        (

        partition sal_11 values less than(to_date('2012-01-01','YYYY-MM-DD')) ,

        partition sal_12 values less than(to_date('2013-01-01','YYYY-MM-DD')) ,

        partition sal_13 values less than(to_date('2014-01-01','YYYY-MM-DD')) ,

        partition sal_14 values less than(to_date('2015-01-01','YYYY-MM-DD')) ,

        partition sal_15 values less than(to_date('2016-01-01','YYYY-MM-DD')) ,

        partition sal_16 values less than(to_date('2017-01-01','YYYY-MM-DD')) ,

        partition sal_other values less than (maxvalue)

        ) nologging;

 

    3.创建一个唯一索引

        CREATE UNIQUE INDEX tb_pt_ind1

        ON tb_pt(sal_date) nologging;

   

    4.为分区表生成数据

        SQL> INSERT INTO tb_pt

        SELECT TRUNC(SYSDATE)+ROWNUM, dbms_random.random, ROWNUM

        FROM dual

        CONNECT BY LEVEL<=5000;

 

        SQL> commit;

 

        SQL> select count(1) from tb_pt partition(sal_11);

 

          COUNT(1)

        ----------

               300

 

        SQL> select count(1) from tb_pt partition(sal_other);

 

          COUNT(1)

        ----------

              2873

 

        SQL> select * from tb_pt partition(sal_12) where rownum < 3;

 

        SAL_DATE      SAL_ID    SAL_ROW

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

        01-JAN-12 -1.356E+09        301

        02-JAN-12 -761530183        302

 

三、使用exp/imp导出导入分区表数据

    1.导出整个分区表

   

        [oracle@node1 ~]$ exp scott/tiger file='/u02/dmp/tb_pt.dmp' log='/u02/dmp/tb_pt.log' tables=tb_pt

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 13:52:18 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing o

        Export done in US7ASCII character set and AL16UTF16 NCHAR character set

        server uses ZHS16GBK character set (possible charset conversion)

        About to export specified tables via Conventional Path ...

        . . exporting table                          TB_PT

        . . exporting partition                         SAL_11        300 rows exported

        . . exporting partition                         SAL_12        366 rows exported

        . . exporting partition                         SAL_13        365 rows exported

        . . exporting partition                         SAL_14        365 rows exported

        . . exporting partition                         SAL_15        365 rows exported

        . . exporting partition                         SAL_16        366 rows exported

        . . exporting partition                      SAL_OTHER       2873 rows exported

        EXP-00091: Exporting questionable statistics.

        EXP-00091: Exporting questionable statistics.

        Export terminated successfully with warnings.

       

        [oracle@node1 ~]$ oerr exp 00091

        00091, 00000, "Exporting questionable statistics."

        // *Cause:  Export was able export statistics, but the statistics may not be

        //          usuable. The statistics are questionable because one or more of

        //          the following happened during export: a row error occurred, client

        //          character set or NCHARSET does not match with the server, a query

        //          clause was specified on export, only certain partitions or

        //          subpartitions were exported, or a fatal error occurred while

        //          processing a table.

        // *Action: To export non-questionable statistics, change the client character

        //          set or NCHARSET to match the server, export with no query clause,

        //          export complete tables. If desired, import parameters can be

        //          supplied so that only non-questionable statistics will be imported,

        //          and all questionable statistics will be recalculated.

 

        在上面的导出中出现了错误提示，即EXP-00091，该错误表明exp工具所在的环境变量中的NLS_LANG与DB中的NLS_CHARACTERSET不一致

        尽管该错误对最终的数据并无影响，但调整该参数来避免异常还是有必要的。因此需要将其设置为一致即可解决上述的错误提示。

       

        SQL> select userenv('language') from dual;

 

        USERENV('LANGUAGE')

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

        AMERICAN_AMERICA.ZHS16GBK

 

        [oracle@node1 ~]$ export NLS_LANG='AMERICAN_AMERICA.ZHS16GBK'   

 

        经过上述设置之后再次导出正常，过程略。

 

    2.导出单个分区

 

        [oracle@node1 ~]$ exp scott/tiger file='/u02/dmp/tb_pt_sal_16.dmp' log='/u02/dmp/tb_pt_sal_16.log' tables=tb_pt:sal_16

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 13:52:38 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing o

        Export done in ZHS16GBK character set and AL16UTF16 NCHAR character set

        About to export specified tables via Conventional Path ...

        . . exporting table                          TB_PT

        . . exporting partition                         SAL_16        366 rows exported

        EXP-00091: Exporting questionable statistics.

        EXP-00091: Exporting questionable statistics.

        Export terminated successfully with warnings

 

        在上面的导出过程中再次出现了统计信息错误的情况，因此采取了对该对象收集统计信息，但并不能解决该错误，但在exp命令行中增

        加statistics=none即可，如下：

        [oracle@node1 ~]$ exp scott/tiger file='/u02/dmp/tb_pt_sal_16.dmp' log='/u02/dmp/tb_pt_sal_16.log' /

        > tables=tb_pt:sal_16 statistics=none

 

        如果要导出多个分区，则在tables参数中增加分区数。如：tables=(tb_pt:sal_15,tb_pt:sal_16)

 

    3.使用imp工具生成创建分区表的DDL语句

        [oracle@node1 ~]$ imp scott/tiger tables=tb_pt indexfile='/u02/dmp/cr_tb_pt.sql' /

        > file='/u02/dmp/tb_pt.dmp' ignore=y

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 13:54:38 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing o

        Export file created by EXPORT:V11.02.00 via conventional path

        import done in US7ASCII character set and AL16UTF16 NCHAR character set

        import server uses ZHS16GBK character set (possible charset conversion)

        . . skipping partition "TB_PT":"SAL_11"                  

        . . skipping partition "TB_PT":"SAL_12"                  

        . . skipping partition "TB_PT":"SAL_13"                  

        . . skipping partition "TB_PT":"SAL_14"                  

        . . skipping partition "TB_PT":"SAL_15"                  

        . . skipping partition "TB_PT":"SAL_16"                  

        . . skipping partition "TB_PT":"SAL_OTHER"               

        Import terminated successfully without warnings.

 

    4.导入单个分区(使用先前备份的单个分区导入文件)

        SQL> alter table tb_pt truncate partition sal_16;   --导入前先将分区实现truncate

 

        Table truncated.

 

        SQL> select count(1) from tb_pt partition(sal_16);

 

          COUNT(1)

        ----------

                 0

 

        SQL> ho imp scott/tiger tables=tb_pt:sal_16 file='/u02/dmp/tb_pt_sal_16.dmp' ignore=y

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 13:55:39 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing o

        Export file created by EXPORT:V11.02.00 via conventional path

        import done in US7ASCII character set and AL16UTF16 NCHAR character set

        import server uses ZHS16GBK character set (possible charset conversion)

        . importing SCOTT's objects into SCOTT

        . importing SCOTT's objects into SCOTT

        . . importing partition               "TB_PT":"SAL_16"

        IMP-00058: ORACLE error 1502 encountered

        ORA-01502: index 'SCOTT.TB_PT_IND1' or partition of such index is in unusable state

        Import terminated successfully with warnings.

 

        收到了ORA-01502错误，下面查看索引的状态，并对其重建索引后再执行导入

        SQL> select index_name ,status from dba_indexes where table_name='TB_PT';  --查看索引的状态

 

        INDEX_NAME                     STATUS

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

        TB_PT_IND1                     UNUSABLE

 

        SQL> alter index TB_PT_IND1 rebuild online;                --重建索引

 

        Index altered.

 

        SQL> ho imp scott/tiger tables=tb_pt:sal_16 file='/u02/dmp/tb_pt_sal_16.dmp' ignore=y  --再次导入成功

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 13:56:15 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing o

        Export file created by EXPORT:V11.02.00 via conventional path

        import done in US7ASCII character set and AL16UTF16 NCHAR character set

        import server uses ZHS16GBK character set (possible charset conversion)

        . importing SCOTT's objects into SCOTT

        . importing SCOTT's objects into SCOTT

        . . importing partition               "TB_PT":"SAL_16"        366 rows imported

        Import terminated successfully without warnings.

       

        SQL> select count(*) from tb_pt partition(sal_16);

 

          COUNT(*)

        ----------

               366

 

    5.导入整个表

        SQL> truncate table tb_pt;    --首先truncate 整个表

 

        Table truncated.

 

        SQL> ho imp scott/tiger tables=tb_pt file='/u02/dmp/tb_pt.dmp' ignore=y indexes=y

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 13:57:10 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing o

        Export file created by EXPORT:V11.02.00 via conventional path

        import done in US7ASCII character set and AL16UTF16 NCHAR character set

        import server uses ZHS16GBK character set (possible charset conversion)

        . importing SCOTT's objects into SCOTT

        . importing SCOTT's objects into SCOTT

        . . importing partition               "TB_PT":"SAL_11"        298 rows imported

        . . importing partition               "TB_PT":"SAL_12"        366 rows imported

        . . importing partition               "TB_PT":"SAL_13"        365 rows imported

        . . importing partition               "TB_PT":"SAL_14"        365 rows imported

        . . importing partition               "TB_PT":"SAL_15"        365 rows imported

        . . importing partition               "TB_PT":"SAL_16"        366 rows imported

        . . importing partition            "TB_PT":"SAL_OTHER"       2875 rows imported

        Import terminated successfully without warnings.

       

        SQL> select count(1) from tb_pt partition(sal_other);

 

          COUNT(1)

        ----------

              2875

 

四、使用expdp/impdb来实现分区表的导入导出

    1.查看导入导出的目录设置

        SQL> select directory_name,directory_path from dba_directories where directory_name='DMP';

 

        DIRECTORY_NAME                 DIRECTORY_PATH

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

        DMP                            /u02/dmp

 

    2.为分区表创建一个本地索引

        create index tb_pt_local_idx

        on tb_pt(sal_id)

        local

        (partition local1,

        partition local2,

        partition local3,

        partition local4,

        partition local5,

        partition local6,

        partition local7)

        ;

 

    3.导出整个表

        [oracle@node1 ~]$ expdp scott/tiger directory=dmp dumpfile=tb_pt.dmp logfile=tb_pb.log tables=tb_pt parallel=3

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 14:04:28 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing options

        Starting "SCOTT"."SYS_EXPORT_TABLE_01":  scott/******** directory=dmp dumpfile=tb_pt.dmp logfile=tb_pb.log tables=

            tb_pt parallel=3                                                                  

        Estimate in progress using BLOCKS method...

        Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

        Total estimation using BLOCKS method: 512 KB

        . . exported "SCOTT"."TB_PT":"SAL_OTHER"                 71.63 KB    2875 rows

        . . exported "SCOTT"."TB_PT":"SAL_11"                    12.54 KB     298 rows

        . . exported "SCOTT"."TB_PT":"SAL_12"                    14.22 KB     366 rows

        . . exported "SCOTT"."TB_PT":"SAL_13"                    14.18 KB     365 rows

        . . exported "SCOTT"."TB_PT":"SAL_14"                    14.18 KB     365 rows

        . . exported "SCOTT"."TB_PT":"SAL_15"                    14.19 KB     365 rows

        . . exported "SCOTT"."TB_PT":"SAL_16"                    14.23 KB     366 rows

        Processing object type TABLE_EXPORT/TABLE/TABLE

        Processing object type TABLE_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT

        Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX

        Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS

        Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS

        Master table "SCOTT"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded

        ******************************************************************************

        Dump file set for SCOTT.SYS_EXPORT_TABLE_01 is:

          /u02/dmp/tb_pt.dmp

        Job "SCOTT"."SYS_EXPORT_TABLE_01" successfully completed at 14:04:51

 

    4.导出多个分区

        [oracle@node1 ~]$ expdp scott/tiger directory=dmp dumpfile=tb_pts.dmp logfile=tb_pt.log /

        > tables=(tb_pt:sal_16,tb_pt:sal_other) parallel=2

        Export: Release 11.2.0.1.0 - Production on Wed Mar 9 14:08:06 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing options

        Starting "SCOTT"."SYS_EXPORT_TABLE_01":  scott/******** directory=dmp dumpfile=tb_pts.dmp logfile=tb_pt.log

            tables=(tb_pt:sal_16,tb_pt:sal_other) parallel=2                        --*/

        Estimate in progress using BLOCKS method...

        Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

        Total estimation using BLOCKS method: 192 KB

        . . exported "SCOTT"."TB_PT":"SAL_OTHER"                 71.63 KB    2875 rows

        . . exported "SCOTT"."TB_PT":"SAL_16"                    14.23 KB     366 rows

        Processing object type TABLE_EXPORT/TABLE/TABLE

        Processing object type TABLE_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT

        Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX

        Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS

        Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS

        Master table "SCOTT"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded

        ******************************************************************************

        Dump file set for SCOTT.SYS_EXPORT_TABLE_01 is:

          /u02/dmp/tb_pts.dmp

        Job "SCOTT"."SYS_EXPORT_TABLE_01" successfully completed at 14:08:17

 

    5.截断分区sal_other

        SQL> alter table tb_pt truncate partition(sal_other);

 

        Table truncated.

 

        SQL> select count(*) from tb_pt partition(sal_other);

 

          COUNT(*)

        ----------

                 0

 

        SQL> select index_name,status,partitioned from dba_indexes where table_name='TB_PT'; --查看索引的状态, TB_PT_IND1不可用

 

        INDEX_NAME                     STATUS   PAR

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

        TB_PT_IND1                     UNUSABLE NO

        TB_PT_LOCAL_IDX                N/A      YES

       

        SQL> select index_name ,partition_name, status from dba_ind_partitions where index_owner='SCOTT';

       

        INDEX_NAME                     PARTITION_NAME                 STATUS

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

        TB_PT_LOCAL_IDX                LOCAL1                         USABLE

        TB_PT_LOCAL_IDX                LOCAL2                         USABLE

        TB_PT_LOCAL_IDX                LOCAL3                         USABLE

        TB_PT_LOCAL_IDX                LOCAL4                         USABLE

        TB_PT_LOCAL_IDX                LOCAL5                         USABLE

        TB_PT_LOCAL_IDX                LOCAL6                         USABLE

        TB_PT_LOCAL_IDX                LOCAL7                         USABLE

       

    6.导入单个分区

        [oracle@node1 ~]$ impdp scott/tiger directory=dmp dumpfile=tb_pts.dmp logfile=tb_pt_imp.log /

        > tables=tb_pt:sal_other skip_unusable_indexes=y table_exists_action=replace

        Import: Release 11.2.0.1.0 - Production on Wed Mar 9 14:13:28 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing options

        Master table "SCOTT"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded

        Starting "SCOTT"."SYS_IMPORT_TABLE_01":  scott/******** directory=dmp dumpfile=tb_pts.dmp logfile=tb_pt_imp.log

            tables=tb_pt:sal_other skip_unusable_indexes=y table_exists_action=replace             --*/

        Processing object type TABLE_EXPORT/TABLE/TABLE

        Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

        . . imported "SCOTT"."TB_PT":"SAL_OTHER"                 71.63 KB    2875 rows

        Processing object type TABLE_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT

        Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX

        Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS

        Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS

        Job "SCOTT"."SYS_IMPORT_TABLE_01" successfully completed at 14:13:33

 

        SQL> select index_name,status,partitioned from dba_indexes where table_name='TB_PT';

 

        INDEX_NAME                     STATUS   PAR

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

        TB_PT_IND1                     VALID    NO

        TB_PT_LOCAL_IDX                N/A      YES

       

        从上面的导入情况可以看出，尽管执行了truncate partition，然而使用impdp导入工具，并且使用参数table_exists_action=replace

        可以避免使用imp导入时唯一和主键索引需要重建的问题。注意，如果没有使用table_exists_action=replace参数，将会收到ORA-39151

        错误，如下

            ORA-39151: Table "SCOTT"."TB_PT" exists. All dependent metadata and data will be skipped due to

                table_exists_action of skip

 

    7.导入整个表

        [oracle@node1 ~]$ impdp scott/tiger directory=dmp dumpfile=tb_pt.dmp logfile=tb_pt_fullimp.log /

        > tables=tb_pt skip_unusable_indexes=y table_exists_action=replace

        Import: Release 11.2.0.1.0 - Production on Wed Mar 9 14:17:35 2011

        Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

        Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

        With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

        Data Mining and Real Application Testing options

        Master table "SCOTT"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded

        Starting "SCOTT"."SYS_IMPORT_TABLE_01":  scott/******** directory=dmp dumpfile=tb_pt.dmp logfile=tb_pt_fullimp.log

            tables=tb_pt skip_unusable_indexes=y table_exists_action=replace                     --*/

        Processing object type TABLE_EXPORT/TABLE/TABLE

        Processing object type TABLE_EXPORT/TABLE/TABLE_DATA

        . . imported "SCOTT"."TB_PT":"SAL_OTHER"                 71.63 KB    2875 rows

        . . imported "SCOTT"."TB_PT":"SAL_11"                    12.54 KB     298 rows

        . . imported "SCOTT"."TB_PT":"SAL_12"                    14.22 KB     366 rows

        . . imported "SCOTT"."TB_PT":"SAL_13"                    14.18 KB     365 rows

        . . imported "SCOTT"."TB_PT":"SAL_14"                    14.18 KB     365 rows

        . . imported "SCOTT"."TB_PT":"SAL_15"                    14.19 KB     365 rows

        . . imported "SCOTT"."TB_PT":"SAL_16"                    14.23 KB     366 rows

        Processing object type TABLE_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT

        Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX

        Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS

        Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS

        Job "SCOTT"."SYS_IMPORT_TABLE_01" successfully completed at 14:17:40

 

五、参数skip_unusable_indexes的作用

    SQL> show parameter skip

 

    NAME                                 TYPE        VALUE

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

    skip_unusable_indexes                boolean     TRUE

 

    该参数允许在导入分区数据时延迟对索引的处理，即先将数据导入，导入后再来重建索引分区。

    在命令行导入中未指定导入参数skip_unusable_indexes时，则对于索引相关的问题，根据数据库初始化参数的值来确定。

    在命令行导入中如果指定了参数skip_unusable_indexes时，则该参数的值优先于数据库初始化参数的设定值。

    skip_unusable_indexes=y对unique index不起作用，因为此时的unique index扮演者constraint的作用，所以在insert数据时index必须被

        更新。

    对于单个分区导入时PK，unique index的处理，必须先重建索引然后进行导入。

    使用impdp数据泵实现导入并使用参数table_exists_action=replace可以解决上述问题，即ORA-01502错误。

 

六、更多参考

 

    有关性能优化请参考

        Oracle 硬解析与软解析

共享池的调整与优化(Shared pool Tuning)

Buffer cache 的调整与优化(一)

Oracle 表缓存(caching table)的使用

 

有关闪回特性请参考

        Oracle 闪回特性(FLASHBACK DATABASE)

Oracle 闪回特性(FLASHBACK DROP & RECYCLEBIN)

Oracle 闪回特性(Flashback Query、Flashback Table)

Oracle 闪回特性(Flashback Version、Flashback Transaction)

 

有关基于用户管理的备份和备份恢复的概念请参考：

        Oracle 冷备份

        Oracle 热备份

        Oracle 备份恢复概念

        Oracle 实例恢复

        Oracle 基于用户管理恢复的处理(详细描述了介质恢复及其处理)

       

    有关RMAN的恢复与管理请参考：

        RMAN 概述及其体系结构

        RMAN 配置、监控与管理

        RMAN 备份详解

        RMAN 还原与恢复

       

    有关Oracle体系结构请参考：

        Oracle 实例和Oracle数据库(Oracle体系结构)

        Oracle 表空间与数据文件

        Oracle 密码文件

        Oracle 参数文件

Oracle 数据库实例启动关闭过程

        Oracle 联机重做日志文件(ONLINE LOG FILE)

        Oracle 控制文件(CONTROLFILE)

        Oracle 归档日志