Parallel Access to External Tables (173)

After the metadata for an external table is created, you can query the external data
directly and in parallel, using SQL. As a result, the external table acts as a view, which
lets you run any SQL query against external data without loading the external data
into the database.

The degree of parallel access to an external table is specified using standard parallel
hints and with the PARALLEL clause. Using parallelism on an external table allows for
concurrent access to the datafiles that comprise an external table. Whether a single file
is accessed concurrently is dependent upon the access driver implementation, and
attributes of the datafile(s) being accessed (for example, record formats).

並行訪問外部表
1. 可以使用並行查詢或者直接查詢訪問外部表後設資料

[@more@]