THE GREAT 8
Oracle8, the latest version of Oracle Server, is designed specifically to address the needs of today's largest, most demanding, and most complex mission-critical database applications. For fast-growing data-warehouse and demanding online transaction processing (OLTP) environments, Oracle8 provides greater scalability, availability, reliability, and manageability than any previous Oracle Server release. At the same time, Oracle8 brings true object capabilities and enhanced complex data support to a mainstream commercial relational database.
Oracle8 extends Oracle Server by providing new capabilities. Oracle8 has high-availability capability regardless of size or platform. Oracle8 also extends Oracle Server to support very large databases (VLDBs) into hundreds of terabytes in size and even larger. For data-warehouse environments, that means larger database, file, and table sizes. For OLTP applications, Oracle8 now supports tens of thousands of concurrent online users.
Oracle8 extends the server's data modeling capabilities to support a new object-relational database model. Today's businesses need ways to deal with more-complex data and applications to model business entities such as purchase orders and parts assemblies. ITmanagers are beginning to use object-oriented programming techniques and middleware as a way to enhance development and deployment of large-scale distributed systems. Oracle8 gives them a way to incorporate this technology with existing relational systems.
Many OLTP applications must support rapidly expanding populations of concurrent users. For these environments, Oracle8 delivers significant improvements: Oracle8-based OLTP applications can now scale into the tens of thousands of concurrent users, offering improved performance as well as enhanced administration and security functions. Through its improved reliability and availability features, Oracle8 offers round-the-clock operations and lights-out management.
The advanced queuing facility of Oracle8 implements database-resident queues, supporting enqueue/dequeue and other services. Enqueue and dequeue can reduce transaction response times. Running in the server, they allow an application to safely remove logic from within a transaction and move it to a background process. Database queues can also be used with transaction processing monitors and message-based middleware to better integrate these facilities with the database server, eliminating redundancies and improving efficiency. Oracle8 includes several other features for improved performance and functionality of OLTP applications. For example, better sharing of runtime data structures reduces per-user memory requirements, improved checkpoint algorithms allow effective use of even larger buffer caches, and new features such as deferrable constraints enhance the flexibility of Oracle for OLTP development.
Oracle8 offers improved support for transaction processing monitors, such as BEA Systems' Tuxedo (www.beasys.com), NCR's TopEnd (www.ncr.com), UniKix Technologies' UniKix (www.unikix.com), and IBM's CICSfor UNIX (www.ibm.com). Enhancements include improved performance, dynamic XA registration, and user-authentication and security-context features.
Data warehouse applications will benefit from enhancements such as parallel execution of insert, update, and delete operations for bulk data operations such as periodic purging of old transactions. Parallel index scans allow for parallel execution of index-driven queries. And partition- and parallel-aware query optimization includes new algorithms for star-query schemas containing bit-mapped indexes, star joins, and parallelism. The improved query optimization dramatically improves query performance against sparse star schemas, where the combination of values in the fact table is a small subset of the possible values.
Additional parallel server improvements in Oracle8 include an integrated Distributed Lock Manager for improved performance and tuneability, and system management views, which allow DBAs to see system performance and operational data across all nodes of a parallel server configuration. Other improvements include transparent application fail-over with automatic reconnections to a surviving instance (in a cluster) and automatic load balancing.
Oracle8's object-relational capability extends the server's data-type system to allow the representation of complex business objects, supporting object-based applications written in popular languages such as C++ and Java. Integrated new object-relational features represent a significant functional and architectural extension of Oracle Server.
The object-relational capabilities also allow users to access existing relational applications and data via object views, a technology unique to Oracle8 that allows relational data to be viewed as objects. Developers can also use object views to integrate new object-based applications with existing relational ones.
Oracle plans to enhance products in its application development product line, including Developer/2000, Designer/2000, and Oracle Express Objects, to support Oracle8's new object-relational features.
With size comes complexity, which Oracle8 addresses with features such as data- and index- partitioning geared toward making database environments more manageable, available, and reliable. Partitioning allows DBAs to perform management operations such as import/export, backup, recovery, and data loading on a portion of a table or index without affecting the availability of other portions of the table or index. Oracle8 supports online addition and removal of partitions as well as parallel data-management (insert, update, delete) operations by partition (see "Divide and Conquer," in this issue).
Flexible indexing options offer choices for OLTP and data warehouse applications, with a variety of performance and availability characteristics. An exchange operation swaps tables with partitions without moving data, which is useful for reorganizing partitions. This is also a migration aid for users of Oracle7 Release 7.3 partition views.
Oracle8 provides automatic, flexible, server-managed backup-and-recovery facilities that are scalable to any hardware configuration. The new server's Recovery Manager runs from Enterprise Manager via an easy-to-use GUI and interfaces with third-party media managers. Recovery Manager also performs backup and recovery and maintains a catalog that tracks which backups have been done and when. Oracle8 also supports incremental backup and recovery, in which only the changed blocks are backed up. This leaves DBAs with smaller backup sets to store and less to process on recovery, which in turn improves performance.
To improve scalability, Oracle8 and Net8 (successor to SQL*Net 2.0) provide efficient connection sharing. With Connection Manager, multiple user sessions and active transactions can occur across a single database connection. A connection-pooling feature utilizes idle connections to support more users. Shared database links permit efficient server communications and enable more-efficient use of Oracle servers as middle tiers in multitier client/server architectures.
New replication capabilities include the Replication API, which enables bidirectional replication of data between Oracle8 servers and systems using Personal Oracle Lite and non-Oracle data stores. Other replication enhancements include parallel propagation, which allows multiple transactions to be applied simultaneously at the target site; reduced code path for improved performance; replication of large objects (LOBs); and query subsetting for mass deployment.
Oracle8 is an important component of Oracle's Network Computing Architecture (NCA). NCA is Oracle's standards-based framework for building distributed object applications for the Web, client/server systems, and corporate intranets. Operating within the NCA framework, Oracle8 supports distributed multitier client/server and Web-based applications. (For more information on NCA, see Product News in the November/December 1996 issue and "Objects at Oracle" in the January/February 1997 issue.)
Enterprises can use NCA-compliant cartridges to extend the functionality of their applications at any tier in a multitier distributed computing environment, including clients, application servers, and database servers.
Migrating from Oracle7 to Oracle8 is fast and simple. A migration utility rebuilds the data dictionary and converts control and log files for existing Oracle7 environments. The utility converts Oracle7 Release 7.1, 7.2, and 7.3 databases into Oracle8 databases and runs in time proportional to the number of database objects and files rather than to the size of those objects or files.
Oracle7 applications can run unchanged against Oracle8; distributed commands from Oracle8 can run unchanged against Oracle7 and vice versa.
Oracle8 is scheduled for general release this summer. For more information, visit Oracle's Web site at www.oracle.com.-PJG