About Other Types of Parallelism

In addition to parallel SQL execution, Oracle Database can use parallelism for the following types of operations:

  • Parallel recovery

  • Parallel propagation (replication)

  • Parallel load (external tables and the SQL*Loader utility)

Like parallel SQL, parallel recovery, propagation, and external table loads are performed by a parallel execution coordinator and multiple parallel execution servers. Parallel load using SQL*Loader, however, uses a different mechanism.

The behavior of the parallel execution coordinator and parallel execution servers may differ, depending on what kind of operation they perform (SQL, recovery, or propagation). For example, if all parallel execution servers in the pool are occupied and the maximum number of parallel execution servers has been started:

  • In parallel SQL and external table loads, the parallel execution coordinator switches to serial processing.

  • In parallel propagation, the parallel execution coordinator returns an error.

For a given session, the parallel execution coordinator coordinates only one kind of operation. A parallel execution coordinator cannot coordinate, for example, parallel SQL and parallel recovery or propagation at the same time.

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