Default: BLOCKS
Purpose
Instructs the source system in a network import operation to estimate how much data will be generated.
Syntax and Description
ESTIMATE=[BLOCKS | STATISTICS]
The valid choices for the ESTIMATE parameter are as follows:
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. (Table analysis can be done with either the SQL ANALYZE statement or the DBMS_STATS PL/SQL package.)
The estimate that is generated can be used to determine a percentage complete throughout the execution of the import job.
Restrictions
The Import ESTIMATE parameter is valid only if the NETWORK_LINK parameter is also specified.
When the import source is a dump file set, the amount of data to be loaded is already known, so the percentage complete is automatically calculated.
The estimate may be inaccurate if either the QUERY or REMAP_DATA parameter is used.
Example
In the following example, source_database_link would be replaced with the name of a valid link to the source database.
> impdp hr TABLES=job_history NETWORK_LINK=source_database_link
DIRECTORY=dpump_dir1 ESTIMATE=STATISTICS
The job_history table in the hr schema is imported from the source database. A log file is created by default and written to the directory pointed to by the dpump_dir1 directory object. When the job begins, an estimate for the job is calculated based on table statistics.