Default: YES
Purpose
Determines whether Data Pump can use Oracle Real Application Clusters (Oracle RAC) resources and start workers on other Oracle RAC instances.
Syntax and Description
CLUSTER=[YES | NO]
To force Data Pump Import to use only the instance where the job is started and to replicate pre-Oracle Database 11g release 2 (11.2) behavior, specify CLUSTER=NO.
To specify a specific, existing service and constrain worker processes to run only on instances defined for that service, use the SERVICE_NAME parameter with the CLUSTER=YES parameter.
Use of the CLUSTER parameter may affect performance because there is some additional overhead in distributing the import job across Oracle RAC instances. For small jobs, it may be better to specify CLUSTER=NO to constrain the job to run on the instance where it is started. Jobs whose performance benefits the most from using the CLUSTER parameter are those involving large amounts of data.
Example
> impdp hr DIRECTORY=dpump_dir1 SCHEMAS=hr CLUSTER=NO PARALLEL=3 NETWORK_LINK=dbs1
This example performs a schema-mode import of the hr schema. Because CLUSTER=NO is used, the job uses only the instance where it is started. Up to 3 parallel processes can be used. The NETWORK_LINK value of dbs1 would be replaced with the name of the source database from which you were importing data. (Note that there is no dump file generated because this is a network import.)
The NETWORK_LINK parameter is simply being used as part of the example. It is not required when using the CLUSTER parameter.