This parameter is useful when you wanted get the approximate size of the dump file. Suppose you have only limited space available in the disk and if you wanted to check whether your dump will be fit into the available space then you can use this parameter to check or estimate the size of the dump with doing the actual export. Some facts are here about estimate_only parameter.

Syntax and Description


If ESTIMATE_ONLY=YES, then Export estimates the space that would be consumed, but quits without actually performing the export operation.


The following shows an example of using the ESTIMATE_ONLY parameter to determine how much space an export of the USERS tablespace will take.

[oracle@orcl ~]$ expdp TABLESPACES=USERS estimate_only=Y estimate=STATISTICS NOLOGFILE=YES

Export: Release - Production on Sat Dec 23 16:01:16 2017

Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.

Username: / as sysdba

Connected to: Oracle Database 11g Enterprise Edition Release - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
Estimate in progress using STATISTICS method...

Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. estimated "CBCM"."CUST_FADS_2548_HIST_GAL" 21.91 GB
. estimated "CBCM"."CUST_FADS_1359_HIST_GAL" 11.76 GB
Total estimation using BLOCKS method: 33.67 GB
Job "SYS"."SYS_EXPORT_TABLESPACE_01" successfully completed at Sat Dec 23 15:56:22 2017 elapsed 0 00:5:57

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