Oracle Tips  by Burleson Consulting

The Data Warehouse Development Life Cycle

Oracle Features for the Data Warehouse

Using Oracle’s Read-Only Tablespaces

These features are essential for maintaining the integrity of an updated Oracle database, but they are not necessary when your Oracle data warehouse is running in read-only mode. As such, many Oracle Remote DBA’s configure their data warehouses to use Oracle’s read-only tablespaces. Read-only tablespaces prohibit update operations against the tablespace. The main purpose of read-only tablespaces is to eliminate the need to perform backup and recovery operations against a static tablespace. Therefore, their primary purpose for the data warehouse is to segregate those parts of the warehouse that are “historic”, and will never be altered from the more recent warehouse information which may be updated.

Note: A read-only tablespace may only be online in the database that created the tablespace. The concept of Oracle read-only tablespaces has not yet been extended to allow multiple instances to access a read-only tablespace (except, of course, with Oracle parallel server).

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This is an excerpt from "High Performance Data Warehousing". To learn more about Oracle, try "Oracle Tuning: The Definitive Reference", by Donald K. Burleson.  You can buy it direct from the publisher at 30% off here:
http://www.rampant-books.com/book_1002_oracle_tuning_definitive_reference_2nd_ed.htm