Often you can severely limit the number of rows acted
on by your operations, substantially improving performance.
Use Partitions
Partitions can benefit end users, DBAs, and application support personnel. For end users, there
are two potential benefits: improved query performance and improved availability for the database.
Query performance may improve because of partition elimination. The optimizer knows what
partitions may contain the data requested by a query. As a result, the partitions that will not
participate are eliminated from the query process. Because fewer logical and physical reads
are needed, the query should complete faster.
Chapter 5: Developing and Implementing Applications 131
NOTE
The Partitioning Option is an extra-cost option for the Enterprise
Edition of the database software.
The availability improves because of the benefits partitions generate for DBAs and application
support personnel. Many administrative functions can be performed on single partitions, allowing
the rest of the table to be unaffected. For example, you can truncate a single partition of a table.
You can split a partition, move it to a different tablespace, or switch it with an existing table (so
that the previously independent table is then considered a partition). You can gather statistics on
one partition at a time. All these capabilities narrow the scope of administrative functions, reducing
their impact on the availability of the database as a whole.
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