??? Parallelism resource limitations of the user??™s consumer group if the Database
Resource Manager is active. (The Database Resource Manager is explained in
Chapter 9 and also later in this chapter.) This is important, because it means
that adaptive parallelism respects resource plans if they??™re in place.
Partition-Based Parallelism
A small subset of Oracle??™s parallel functionality is based on the number of partitions or
subpartitions accessed by the statement to be parallelized. For block-range parallelism,
the piece of data each PE process works on is a range of blocks. For partition-based
parallelism, the pieces of data that drive parallelism are partitions or subpartitions of a
table. The operations in which parallelism is based on the number of partitions or
subpartitions include the following:
??? Updates and deletes
??? Index scans
??? Index creation and rebuilds on partitioned tables
Oracle and Parallelism | 175
Parallelism for partitions and subpartitions of a table
Oracle8 introduced support for parallel Data Manipulation Language (DML), or the
ability to execute INSERT, UPDATE, and DELETE statements in parallel.
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