使用expdp導(dǎo)出命令時(shí)，通常需要評(píng)估導(dǎo)出文件的大小來(lái)作為空間是否足夠的依據(jù)，
特別是在做全庫(kù)導(dǎo)出的場(chǎng)景中。
設(shè)置參數(shù)estimate_only=y|n 來(lái)指定是否僅做評(píng)估而不導(dǎo)數(shù)據(jù)
設(shè)置參數(shù)estimate=statistic 根據(jù)最近統(tǒng)計(jì)值估算對(duì)象占用空間
測(cè)試過(guò)程如下：
[oracle@hisdb1:/home/oracle]$ expdp \'/ as sysdba\' full=y estimate_only=y estimate=statistics
Export: Release 11.2.0.4.0 - Production on Fri Feb 18 16:20:27 2022
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, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
Starting "SYS"."SYS_EXPORT_FULL_01": "/******** AS SYSDBA" full=y estimate_only=y estimate=statistics
Estimate in progress using STATISTICS method...
. estimated "SYSTEM"."REPCAT$_RESOLUTION_STATISTICS" 0 KB
. estimated "SYSTEM"."REPCAT$_RESOL_STATS_CONTROL" 0 KB
. estimated "SYSTEM"."REPCAT$_RUNTIME_PARMS" 0 KB
. estimated "SYSTEM"."REPCAT$_SITES_NEW" 0 KB
. estimated "SYSTEM"."REPCAT$_SITE_OBJECTS" 0 KB
. estimated "SYSTEM"."REPCAT$_SNAPGROUP" 0 KB
. estimated "SYSTEM"."REPCAT$_TEMPLATE_OBJECTS" 0 KB
. estimated "SYSTEM"."REPCAT$_TEMPLATE_PARMS" 0 KB
. estimated "SYSTEM"."REPCAT$_TEMPLATE_REFGROUPS" 0 KB
. estimated "SYSTEM"."REPCAT$_TEMPLATE_SITES" 0 KB
. estimated "SYSTEM"."REPCAT$_TEMPLATE_TARGETS" 0 KB
. estimated "SYSTEM"."REPCAT$_USER_AUTHORIZATIONS" 0 KB
. estimated "SYSTEM"."REPCAT$_USER_PARM_VALUES" 0 KB
. estimated "SYSTEM"."SQLPLUS_PRODUCT_PROFILE" 0 KB
Total estimation using STATISTICS method: 29.25 MB
Job "SYS"."SYS_EXPORT_FULL_01" successfully completed at Fri Feb 18 16:20:42 2022 elapsed 0 00:00:14