CLUSTER

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 Export 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 export 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

The following is an example of using the CLUSTER parameter:

> expdp hr DIRECTORY=dpump_dir1 DUMPFILE=hr_clus%U.dmp CLUSTER=NO PARALLEL=3

This example starts a schema-mode export (the default) of the hr schema. Because CLUSTER=NO is specified, the job uses only the instance on which it started. (If the CLUSTER parameter had not been specified at all, then the default value of Y would have been used and workers would have been started on other instances in the Oracle RAC, if necessary.) The dump files will be written to the location specified for the dpump_dir1 directory object. The job can have up to 3 parallel processes.