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Data Pump Access Methods
Direct path
- Supported for many export and import operations
- Multiple, parallel direct path streams
External table
- Used, for example, if filter with QUERY parameter
- 10g supports write to external tables
- Parallel query and parallel DML support
Datapump automatically chooses method
Notes:
Datapump has two methods available for exporting and importing data: direct path (like the old export direct path) and external tables. Notable points are:
Unlike the original utility, datapump import can use the direct path technique, increasing the performance of import operations.
As the name implies, the external tables method uses external tables (the external tables feature was introduced with Oracle9i). 10g enhances external tables to allow writing to external files.
Datapump will choose the method automatically and transparently. For example, if you use the QUERY parameter to filter data, datapump will choose the external table access method. There are several additional restrictions on direct path access; refer to chapter 1 of the Oracle10g Database Utilities manual for a complete list of restrictions.