Oracle9i promises some
Dec 18, 2000 -
© 2001 TechRepublic, Inc.
In an earlier
article, we covered some of the new data warehouse characteristics of Oracle
9i and discussed a few of the version's changes. Continuing with our
overview, we'll turn our attention now to the database, availability, and
WebServer enhancements in Oracle 9i.
Improved systems management
Oracle has been struggling for many years to make it easy for database
administrators to configure a complex Oracle environment. At the lowest level,
all of the Oracle configuration information exists inside flat files, and it is
the responsibility of the Oracle DBA to know where these files are and to
understand the internal meaning of thousands of database parameters.
Oracle has attempted to get around this cumbersome aspect of database management
by creating wizard-based tools that will automatically generate the
configuration syntax and write them to the database configuration files. In
Oracle8, these wizard tools are quite clumsy and often make errors, but in
Oracle9i, the tools are significantly improved.
Oracle is also beginning to step out of its traditional database-only monitoring
with products that actually monitor the relative CPU load of different servers
in an extended WebServer environment. Oracle promises to provide tools that will
monitor disk space in memory usage on Oracle servers. This is a rather
surprising move for Oracle, which previously limited its monitoring to the
activity within the database management system itself. With this new Oracle9i
feature, Oracle is competing with third-party server monitoring vendors such as
BMC Software and Tivoli.
One of the most exciting features of Oracle9i is the improved memory
management that allows Oracle's system global area (SGA) to be resized. Prior to
Oracle9i, database administrators had to define the RAM and memory
regions for the SGA (via the init.ora parameter file), and they had no control
over resizing those memory regions without shutting down and restarting the
In Oracle9i, the database administrator can dynamically alter the SGA and
remove space from all of the major areas of the SGA, including the database
buffers, the shared pool, and other integral components of an Oracle database.
For example, if the DBA detects that the shared pool is short on storage, he or
she will be able to dynamically remove space from the database block buffers and
reallocate them to the shared pool.
This ability to dynamically change the SGA will dramatically increase the
availability of 24/7 Oracle systems and make it far easier to keep Oracle
databases running continuously for long periods of time.
In another interesting turn of events, Oracle9i now promises database
recovery directly from the online redo logs. Oracle redo logs contain the
"after" images of all changed rows in the Oracle database and are used
to roll-forward the database in cases of disk failure. Prior to Oracle9i,
Oracle expressly refused to support software that read information from the
online redo logs. But now, Oracle allows this information to be read directly
from the online redo logs, which will greatly improve the performance and
maintenance of 24/7 online Oracle database systems. For example, by allowing
reads from the online redo logs, an existing database can be cloned and
restarted while remaining synchronized with the original database.
High availability enhancements
To enhance its features for handling high availability needs, Oracle has
implemented a standard technique used by Oracle DBAs for many years. When
systems require continuous availability, the Oracle database administrator makes
a copy of the Oracle database and keeps it in recovery mode. For archive
purposes, redo log files are generated from the primary database and then
transferred to the other database server and fed into the recovering database.
This effectively keeps the standby database very close to the production
database in terms of the currency of the data.
Oracle has incorporated this common DBA trick into the base product within
Oracle9i as a new tool called the Data Guard Broker. The tool is designed
to manage all of the activities of a primary and standby database and to make
the operational application of the redo logs more transparent to the system.
With Oracle commitment to Web-based access, Oracle is now offering some new
tools for monitoring and managing the WebServer environment.
Web site statistics
Oracle has implemented WebServer statistics with Oracle Clickstream
Intelligence. Clickstream collects Web access data for Web site traffic
analysis, customer profiling, and real-time recommendations. This is similar to
ordinary WebServer statistics where the administrator can view the number of
hits for each Web page, the access patterns by hour of the day and day of the
week, and the specific access paths for individual users. Clickstream technology
enables Oracle9i to offer customized recommendations.
Oracle has greatly improved its WebServer software by adding the Oracle9i
database appliance. This database appliance communicates closely with the
WebServer software, allowing multiple Web servers to balance the load of
connections to the Oracle databases. Oracle9i makes it easier for Web
developers to balance the load between multiple Web servers in many e-commerce
It's vital to separate the hype from the facts of any Oracle release. Oracle,
just like all software vendors, glamorizes their new features and engages in
lavish advertising campaigns. But all hype aside, Oracle9i has some very
useful new features and tools that will help Oracle keep its position as the
world's most popular database.