racle has given its grid-ready, next-generation database the ability to manage itself and assume the burden of daily management tasks from the database administrator (DBA). During a session dedicated to the Database 10g product at the OracleWorld Conference in San Francisco this past week, Richard Sarwal, vice president of server performance and data server applied technology for Oracle, listed five main database manageability challenges that DBAs face today. He stressed that they all occur outside the database itself:
- Application and SQL management
- Backup and recovery
- System requirements management
- Storage management
- Space management
Oracle has built functionality into its new database product that enables it to meet each of these challenges with only minimal intervention from administrators. “10g is pulling all those things that take place outside the database inside the database,” said Sarwal.
How Database 10g Was Built
According to Sarwal, the first thing Oracle did was build a repository inside the database for raw system statistics and object data. The result was the Automatic Workload Repository (AWR). By default, 10g retrieves database system data and dumps it onto disk in the AWR every 30 minutes. Functioning as the database’s own data warehouse, this data collection informs Database 10g‘s self-management.
Next, Oracle had to ensure that the database would know how to use this data, which led to the creation of the Automatic Database Diagnostic Monitor (ADDM). Sarwal calls ADDM (pronounced “Adam”) the brains of the database. Its role is to automatically pore through all the infrastructure data in the AWR, detect patterns of use, and produce graphical diagnostics reports that include recommendations for improving performance. It can also prompt server-generated alerts when bottlenecks, “hot spots,” and other performance problems occur.
“Let the Database Manage Storage”
Automatic Storage Management (ASM) is another new Database 10g feature that Oracle is touting. Andy Mendelsohn, Senior Vice President, Oracle Database and Application Server Technologies, describes it as a built-in, high-performance file system and disk manager. Mendelsohn says ASM is based on the principle that the database knows better how to manage storage than its administrators do. “Give the database the raw disk and let the database manage the storage for you,” he said.
The way it accomplishes this is by striping and mirroring data across modular storage arrays (i.e., low-cost storage-like disks), treating the database grid as a large pool of storage rather than separate volumes. ASM simultaneously performs automatic I/O tuning among disks and auto load-balancing based on user-defined requirements. The need for a volume manager and file systems is virtually eliminated, and ASM automatically remirrors when a disk fails.
Self-management, explained Executive Vice President for Server Technologies, Chuck Rozwat in a keynote address Wednesday, means that the database system is capable of taking a workload and figuring out where to run it in order to meet predefined requirements. For example, administrators can predefine a Quality of Service level or define a threshold for CPU usage and let Oracle 10g provision the workload to meet those needs.
Flashback Database: Single-command Recovery
Oracle has built Flashback features into 10g that will replace the old recovery method of restoring data from tape backups. A fundamental change in 10g is the shift in storage media from tape to disk. Mendelsohn explained that the use of tapes dates back decades to when tape was cheaper than disk. But now that the two media are nearly equal in cost, why not use disk, he argues. Tape recovery is linear, so administrators have to recover the database at a given point in time and roll the changes forward. Disk, on the other hand, enables random access recovery where only the needed data is restored.
Juan Loaiza, Oracle’s vice president of systems technologies, describes the Flashback Database feature as “a rewind button for the database.” A Flashback Log inside Database 10g acts as a continuous backup. It captures old versions of changed blocks, operating on only the changed data. An administrator can replay the log to restore a database and it restores only the changed blocks.
All this internal intelligence promises reduced failover times with faster recognition and restart. Loaiza said, “we’re trading disk space, which is cheaper these days, for downtime, which is expensive.”
The approximately 2,000 attendees of Wednesday’s keynote reacted enthusiastically to a demonstration of the new Flashback recovery features.
Oracle Database 10g is slated for release at the end of 2003.