linuxsir首页 LinuxSir.Org | Linux、BSD、Solaris、Unix | 开源传万世,因有我参与欢迎您!
网站首页 | 设为首页 | 加入收藏
您所在的位置:主页 > Linux数据库 >

Oracle 11g版本expdp的COMPRESSION参数压缩比堪比“gzip -9”

时间:2016-10-16  来源:未知  作者:linuxsir首页

1.Oracle 11g中expdp帮助页中关于COMPRESSION参数的描述
secooler@secDB /home/oracle$ expdp -help
……
COMPRESSION
Reduce the size of a dump file.
Valid keyword values are: ALL, DATA_ONLY, [METADATA_ONLY] and NONE.
……

可见,11g中的COMPRESSION参数提供四个选项,分别是ALL、DATA_ONLY、METADATA_ONLY和NONE,非常的丰富,稍后我们将使用ALL参数进行操作。

2.Oracle 10g中关于COMPRESSION参数的描述如下
Keyword              Description (Default)
---------------------------------------------------------------------
……
COMPRESSION          Reduce size of dumpfile contents where valid
                      keyword values are: (METADATA_ONLY) and NONE.
……
10g中的COMPRESSION参数只提供METADATA_ONLY和NONE两个选项,基本上没有提供压缩功能。

3.使用11g EXPDP工具的四个压缩参数分别生成四个dump文件
1)使用ALL参数
secooler@secDB /expdp$ expdp sec/sec dumpfile=sec_ALL.dmp logfile=sec_ALL.log tables=t directory=dump_dir compression=ALL

Export: Release 11.2.0.1.0 - Production on Sat Mar 20 22:48:52 2010

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 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "SEC"."SYS_EXPORT_TABLE_01":  sec/******** dumpfile=sec_ALL.dmp logfile=sec_ALL.log tables=t directory=dump_dir compression=ALL
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 136 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "SEC"."T"                                  14.26 MB 1155520 rows
Master table "SEC"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SEC.SYS_EXPORT_TABLE_01 is:
  /expdp/sec_ALL.dmp
Job "SEC"."SYS_EXPORT_TABLE_01" successfully completed at 22:49:08

2)使用DATA_ONLY参数
secooler@secDB /expdp$ expdp sec/sec dumpfile=sec_DATA_ONLY.dmp logfile=sec_DATA_ONLY.log tables=t directory=dump_dir compression=DATA_ONLY

Export: Release 11.2.0.1.0 - Production on Sat Mar 20 22:49:32 2010

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 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "SEC"."SYS_EXPORT_TABLE_01":  sec/******** dumpfile=sec_DATA_ONLY.dmp logfile=sec_DATA_ONLY.log tables=t directory=dump_dir compression=DATA_ONLY
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 136 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "SEC"."T"                                  14.26 MB 1155520 rows
Master table "SEC"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SEC.SYS_EXPORT_TABLE_01 is:
  /expdp/sec_DATA_ONLY.dmp
Job "SEC"."SYS_EXPORT_TABLE_01" successfully completed at 22:49:48

3)使用METADATA_ONLY参数
secooler@secDB /expdp$ expdp sec/sec dumpfile=sec_METADATA_ONLY.dmp logfile=sec_METADATA_ONLY.log tables=t directory=dump_dir compression=METADATA_ONLY

Export: Release 11.2.0.1.0 - Production on Sat Mar 20 22:50:16 2010

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 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "SEC"."SYS_EXPORT_TABLE_01":  sec/******** dumpfile=sec_METADATA_ONLY.dmp logfile=sec_METADATA_ONLY.log tables=t directory=dump_dir compression=METADATA_ONLY
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 136 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "SEC"."T"                                  111.7 MB 1155520 rows
Master table "SEC"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SEC.SYS_EXPORT_TABLE_01 is:
  /expdp/sec_METADATA_ONLY.dmp
Job "SEC"."SYS_EXPORT_TABLE_01" successfully completed at 22:50:27

4)使用NONE参数
secooler@secDB /expdp$ expdp sec/sec dumpfile=sec_NONE.dmp logfile=sec_NONE.log tables=t directory=dump_dir compression=NONE

Export: Release 11.2.0.1.0 - Production on Sat Mar 20 22:50:43 2010

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 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "SEC"."SYS_EXPORT_TABLE_01":  sec/******** dumpfile=sec_NONE.dmp logfile=sec_NONE.log tables=t directory=dump_dir compression=NONE
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 136 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "SEC"."T"                                  111.7 MB 1155520 rows
Master table "SEC"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SEC.SYS_EXPORT_TABLE_01 is:
  /expdp/sec_NONE.dmp
Job "SEC"."SYS_EXPORT_TABLE_01" successfully completed at 22:50:53

4.比较生成的四个dump文件大小
secooler@secDB /expdp$ du -sm sec*.dmp
15      sec_ALL.dmp
15      sec_DATA_ONLY.dmp
112    sec_METADATA_ONLY.dmp
112    sec_NONE.dmp
secooler@secDB /expdp$ du -sb sec*.dmp
14987264        sec_ALL.dmp
14987264        sec_DATA_ONLY.dmp
117223424      sec_METADATA_ONLY.dmp
117223424      sec_NONE.dmp

实验表明,使用ALL参数和DATA_ONLY参数生成的备份文件基本一样大;使用METADATA_ONLY参数与NONE参数效果一样。

使用压缩与不进行压缩的比率是:15/112约等于1/7!
这才是真正的压缩。

5.使用“gzip -9”对未压缩的备份文件进行压缩,做一下比较
secooler@secDB /expdp$ gzip -9 sec_NONE.dmp
secooler@secDB /expdp$ du -sm sec*dmp*
15      sec_ALL.dmp
15      sec_DATA_ONLY.dmp
112    sec_METADATA_ONLY.dmp
15      sec_NONE.dmp.gz
secooler@secDB /expdp$ du -sb sec*dmp*
14987264        sec_ALL.dmp
14987264        sec_DATA_ONLY.dmp
117223424      sec_METADATA_ONLY.dmp
14717055        sec_NONE.dmp.gz

14987264与14717055的区别,相差甚微,基本相同,“gzip -9”稍胜一点点(也许在您的具体环境下“gzip -9”会逊色一点点)。

6.小结
Oracle 11g的EXPDP工具提供了真正意义上的“备份压缩”,这个技术在备份空间不足的情况下非常实用。
Oracle在改进和优化中不断的前进,慢慢体会吧。

更多Oracle相关信息见Oracle 专题页面 http://www.linuxidc.com/topicnews.aspx?tid=12

友情链接