Top Ten New Features in Oracle9i

 Oracle9i is the latest major version of the Oracle database. This release covers a broad range of functionality, expanding the reach and depth of the features in Oracle8i.

We have updated our Oracle Essentials book to cover the new features in Oracle9i. The following list is, in our judgment, the ten most significant new facets of the Oracle9i database--plus one more feature as a lagniappe.

1.    Real Application Clusters: If you have paid attention to any of the hype surrounding the launch of Oracle9i, you have no doubt heard about Real Application Clusters. In a nutshell, Real Application Clusters are a way to have an Oracle9i database spread across multiple machines in a cluster of servers, with each server extending both the scalability and the availability of the entire cluster.

Real Application Clusters use a technology called cache fusion to make the existence of a cluster transparent to an application. You can run any type of application, from an OLTP (online transaction processing) application to a data warehouse, on a Real Application Clusters database, without modifying your code.

2.    Dynamic Memory Pools: With Oracle9i, you can adjust the size of the memory pools (buffer pool, shared pool, and large pool) without having to stop and restart the server.

3.    Data Guard: This new feature automatically handles standby databases, from creation to maintenance, and failover.

4.    Automatic Undo Management: Rather than having to define and manage rollback segments, you can simply define an Undo tablespace and let Oracle9i take care of the rest.

5.    Flashback Query: This is a nice little feature that allows you to run a query against the database and return results as they would have been produced at an earlier time. Flashback Query uses the same mechanisms as multiversion read consistency, so it's like getting a feature for free.

6.    XMLType: This is a new datatype that lets you store native XML documents directly in the database. XMLType eliminates the need to parse the documents coming into and out of the database.

7.    List Partitioning: This feature offers an additional way to partition data, based on a list of values. If you are using partitions to isolate maintenance operations, List Partitioning could come in handy.

8.    FastStart Recovery: This new feature allows you to simply specify the amount of time you want to spend recovering a database. Oracle9i will use the indicated time to automatically issue checkpoints.

9.    Two-Pass Recovery: One of the behind-the-scenes improvements in Oracle9i is Two-Pass Recovery, which allows the database to be reopened for use as soon as roll-forward recovery is completed, without having to wait for the entire rollback process to finish.

10.                       Zero Data Loss: With Oracle9i, you can now specify Zero Data Loss, which means that all writes to the local log file will also be written to the log file of the standby database. This feature means that the standby database is always in exactly the same state as the active database, so that no data will be lost in the event of a failure.

Bonus Tip

Label Security: This feature gives you the ability to specify security, based on values, which gives you a finer grain of control that is useful if you are creating virtual private databases.