Database Reference
In-Depth Information
3.5
Enhancing the Physical Architecture
Architecturally expanding options for Oracle Database we will briefly intro-
duce are as follows:
Oracle Managed Files (OMF).
Oracle Partitioning.
Various forms of Replication.
Standby/fail-over databases.
Clustering technology.
3.5.1
Oracle Managed Files
Oracle Managed Files (OMF) will automatically create and drop datafiles,
redo logs, archives, and Controlfiles in the operating system. No administra-
tor intervention is required in the operating system. The big problem with
OMF is serious performance impact. The DB_CREATE_FILE_DEST con-
figuration parameter is used to specify placement of datafiles, redo logs, and
Controlfiles. Specifying the DB_CREATE_ONLINE_LOG_DEST_
n
parameters overrides the DB_CREATE_FILE_DEST setting by managing
placement of Controlfiles and redo logs. If more than one (one to five)
DB_CREATE_ONLINE_LOG_DEST_
n
destinations are specified, then
both redo logs are duplexed and Controlfiles are multiplexed. Duplexing and
multiplexing being essentially the same thing in this situation.
3.5.2
Partitioning
Oracle Partitioning allows the splitting of large tables into separate physical
spaces. As a result, different physical spaces or partitions can be operated on
individually or in groups, running in parallel. Performance gains using Ora-
cle Partitioning can be substantial.
Partitions can be of various different types:
Range partitions split a table based on distinct ranges of values such
as quarters in a year.
List partitions split a table based on specific lists of values such as
state names in the United States. For example, a partition containing
data representing the Northeast United States could contain states
such as NY, NJ, and PA for New York, New Jersey, and Pennsylvania,
