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使用EXPDP在完成数据导出时，可以使用ESTIMATE参数评估待导出数据库对象的大小，简单演示一下，供参考。1.查看有关ESTIMATE参数的帮助信息1)查看命令行帮助信息ora10g@secDB /expdp$ expdp help=y……ESTIMATE Calculate job estimates where the valid keywords are:(BLOCKS) and STATISTICS.……2)Oracle官方文档中关于ESTIMATE参数的描述参考链接：引用内容如下：
ESTIMATE
Default: BLOCKS
Purpose
Specifies the method that
Export will use to estimate how
much disk space each table in the export job will consume (in bytes).
The estimate is printed in the log file and displayed on the client's
standard output device. The estimate is for table row data only; it does
not include metadata.
Syntax and Description
ESTIMATE={BLOCKS | STATISTICS}
BLOCKS - The estimate is calculated by multiplying the
number of database blocks used by the source objects, times the
appropriate block sizes.
STATISTICS - The estimate is calculated using statistics
for each table. For this method to be as accurate as possible, all
tables should have been analyzed recently.
Restrictions
If the Data Pump export job involves compressed tables, the default
size estimation given for the compressed table is inaccurate when ESTIMATE=BLOCKS
is used. This is because the size estimate does not reflect that the
data was stored in a compressed form. To get a more accurate size
estimate for compressed tables, use ESTIMATE=STATISTICS.
Example
The following example shows a use of the ESTIMATE
parameter in which the estimate is calculated using statistics for the employees
table:
> expdp hr/hr TABLES=employees ESTIMATE=STATISTICS DIRECTORY=dpump_dir1
DUMPFILE=estimate_stat.dmp2.显式指定ESTIMATE参数为BLOCKSora10g@secDB /expdp$ expdp sec/sec directory=expdp_dir dumpfile=sec.dmp ESTIMATE=BLOCKSExport: Release 10.2.0.3.0 - 64bit Production on Saturday, 10 April, 2010 6:23:26Copyright (c) 2003, 2005, Oracle. All rights reser
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