|Oracle® Database Administrator's Guide
10g Release 2 (10.2)
|PDF · Mobi · ePub|
This section describes new features of the Oracle Database 10g Release 2 (10.2) and provides pointers to additional information. New features information from previous releases is also retained to help those users migrating to the current release.
The following sections describe the new features in Oracle Database:
Transparent data encryption
CREATE TABLE or
ALTER TABLE commands, you can specify table columns for which data is encrypted before being stored in the datafile. If users attempt to circumvent the database access control mechanisms by looking inside datafiles directly with operating system tools, encryption prevents such users from viewing sensitive data.
See Also:Oracle Database Security Guide for information on Transparent Data Encryption.
Increased maximum number of partitions per schema object
The maximum number of partitions and subpartitions that can be defined for a table or index has been increased to 1024K - 1.
DML error logging
A new error logging clause for all DML statements enables certain types of errors (for example, constraint violations or data conversion errors) to be logged to an error logging table, allowing the statement to continue instead of terminating and rolling back.
See Also:"Inserting Data with DML Error Logging"
Enhancements to Automatic Shared Memory Management
The Streams Pool is now also automatically tuned when automatic shared memory management is enabled. A new view,
V$SGA_TARGET_ADVICE, provides information to help with tuning
Improved automatic tuning of undo retention results in fewer "
ORA-01555: snapshot too old" messages.
Automatic tuning of undo retention now always tunes for the maximum possible retention for the undo tablespace based on tablespace size and current system activity. This improves the success rate of Oracle Flashback operations and long-running queries.
Note:This new tuning method for maximum possible retention applies only to fixed size undo tablespaces. For
AUTOEXTENDtablespaces, the behavior is unchanged.
See Also:"Undo Retention"
The Segment Advisor now reports tables with excessive row chaining.
See Also:"Using the Segment Advisor"
The Segment Advisor now runs automatically during the maintenance window.
Upon installation, a Scheduler job is automatically created to run the Segment Advisor during the maintenance window. You can also continue to run the Segment Advisor manually. The automatically run Segment Advisor (the "Automatic Segment Advisor") examines statistics on the entire database and selects segments and tablespaces to analyze. You can view recommendations with Enterprise Manager, with the
DBA_ADVISOR_* views, or with the new
See Also:"Using the Segment Advisor"
Enhancements to the online segment shrink capability
Online segment shrink now supports:
IOT overflow segments (both standalone and as a dependent object of an IOT index segment)
See Also:"Shrinking Database Segments Online"
Enhancements to online table redefinition
Online redefinition of tables now supports:
Redefining a single partition of a partitioned table
Clustered tables, Advanced Queuing queue tables, and materialized view logs
Object data types (objects, VARRAYs, and nested tables, including nested table dependent objects)
NOT NULL constraints
Preservation of table statistics
Parallel execution for Long-to-LOB migration
In addition, dependent PL/SQL package recompilation is no longer required when the redefined table has the same number, types, and order of columns as the original table.
See Also:"Redefining Tables Online"
Support for XMLTypes in the transportable tablespace facility
Enhancements to space management
The DBMS_SPACE_ADMIN package provides new tools to troubleshoot space management problems.
Control files no longer need to be recreated when changing certain configuration parameters
Control files can now dynamically grow in size when you increase the values of the following parameters:
See Also:"When to Create New Control Files"
Tablespace low-space alert thresholds by free space remaining
Low-space alert thresholds for locally managed tablespaces can now be by percent full or by free space remaining (in KB). Free-space-remaining thresholds are more useful for very large tablespaces.
See Also:"Managing Tablespace Alerts"
Fast partition split is now supported for partitioned index-organized tables.
Automatically enabled resource manager
The Resource Manager no longer needs to be enabled at startup to quiesce the database or to activate a resource plan when a Scheduler window opens.
Enhanced Resource Manager monitoring
The Resource Manager now provides more extensive statistics on sessions, plans, and consumer groups, enabling you to better monitor and tune your Resource Manager settings.
See Also:"Monitoring Results"
Automatic Storage Management (ASM) files are now accessible through an XML DB virtual folder
ASM files can now be accessed through the XML DB repository, either programmatically or with protocols like FTP and HTTP/WebDAV.
Automatic Storage Management now has a command-line utility (ASMCMD)
With ASMCMD you can easily view and manipulate files and directories within disk groups. ASMCMD can list the contents of disk groups, perform searches, create and remove directories and aliases, display space utilization, and more.
See Also:Oracle Database Utilities
Automatic Storage Management now supports high-redundancy (3-way mirrored) files in normal redundancy disk groups
Individual files in a normal redundancy disk group can be specified as high redundancy (with 3-way mirroring) by creating the file with a template that has the redundancy attribute set to
HIGH. This applies when explicitly naming a template when creating a file, or when modifying a system default template for the disk group. In addition, the system default template
CONTROLFILE in normal redundancy disk groups now has the redundancy attribute set to
Automatic Storage Management (ASM) supports multiple database versions
ASM maintains forward and backward compatibility between most 10.x versions of Oracle Database and 10.x versions of ASM. That is, any combination of versions 10.1.x.y and 10.2.x.y for either the ASM instance or the database instance works correctly, with this caveat: For a 10.1.x.y database instance to connect to a 10.2.x.y ASM instance, the database must be version 10.1.0.3 or later.
DBMS_FILE_TRANSFER package can now copy files between a local file system and an Automatic Storage Management (ASM) disk group.
DBMS_FILE_TRANSFER package can use a local file system or an ASM disk group as the source or destination for a file transfer. You can now copy files from ASM to the file system or from the file system to ASM.
ALTER DISKGROUP command has a new
REBALANCE WAIT clause.
ALTER DISKGROUP commands that cause a rebalance of an ASM disk group—commands that add, drop, or resize disks, or the command that starts a manual rebalance operation—can now wait until the rebalance operation completes before returning. This is especially useful in scripts.
Enhancements to the Scheduler
The Scheduler supports a new type of object called a chain, which is a grouping of programs that are linked together for a single, combined objective. Scheduler jobs can now be started when a specified event occurs, and the Scheduler can raise events when a job state changes (for example, from running to complete).
The Scheduler also has an expanded calendaring syntax that enables you to define more complex schedules, such as "the last work day of each fiscal quarter." Existing schedules can be combined to create composite schedules.
See Also:"Using Schedules"
PURGE for partitioned tables
To avoid running into resource constraints, the
PURGE command for a partitioned table drops the table in multiple transactions, where each transaction drops a subset of the partitions or subpartitions and then commits. If the
PURGE command fails, you can take corrective action, if any, and then restart the command.
See Also:"Dropping Partitioned Tables"
Server manageability features are introduced in "Server Manageability".
Automatic system task maintenance is discussed in Chapter 23, "Managing Automatic System Tasks Using the Maintenance Window".
Oracle Database lets you create single-file tablespaces, called bigfile tablespaces, which can contain up to 232 or 4G blocks. The benefits of bigfile tablespaces are the following:
They significantly enhance the storage capacity of an Oracle Database.
They reduce the number of datafiles needed for an ultra large database.
They simplify database management by providing datafile transparency.
Multiple default temporary tablespace support for SQL operations
You can create a temporary tablespace group that can be specifically assigned to users in the same way that a single temporary tablespace is assigned. A tablespace group can also be specified as the default temporary tablespace for the database.
RENAME TO clause of the
ALTER TABLESPACE statement enables you to rename tablespaces.
Cross-platform transportable tablespaces
Tablespaces can be transported from one platform to another. The RMAN
CONVERT command is used to do the conversion.
Oracle Database creates an auxiliary system tablespace called
SYSAUX at database creation. This tablespace can be used by various Oracle Database features and products, rather than saving their data in separate tablespaces or in the
Automatic Storage Management
Automatic Storage Management provides a logical volume manager integrated with Oracle Database, eliminating the need for you to purchase a third-party product. Oracle Database creates Oracle-managed files within user-defined disk groups that provide redundancy and striping.
DROP DATABASE statement lets you delete a database and all of its files that are listed in the control file.
Oracle Flashback Transaction Query
This feature introduces the
FLASHBACK_TRANSACTION_QUERY view, which lets you examine changes to the database at the transaction level. As a result, you can diagnose problems, perform analysis, and audit transactions.
Oracle Flashback Version Query
Using undo data stored in the database, you can now view multiple changes to one or more rows, along with the metadata for the changes.
Oracle Flashback Table
TABLE statement lets you quickly recover a table to a point in time in the past without restoring a backup.
Oracle Flashback Drop
Oracle Database now provides a way to restore accidentally dropped tables. When tables are dropped, they are placed into a recycle bin from which they can later be recovered.
Enhanced online redefinition
New procedures have been added to the
DBMS_REDEFINITION package that automate the cloning of dependent objects such as indexes, triggers, privileges, and constraints. Some restrictions have been lifted, allowing more types of tables to be redefined.
Automatic statistics collection
You no longer need to specify the
MONITORING keyword in the
CREATE TABLE or
ALTER TABLE statement to enable the automatic collecting of statistics for a table. Statistics are now collected automatically as controlled by the
STATISTICS_LEVEL initialization parameter. Automatic statistics collection is the default.
Oracle Database provides advanced scheduling capabilities through the database Scheduler.
Database Resource Manager enhancement
The following are enhancements to the Database Resource Manager:
Adaptive consumer group mapping
You can configure the Database Resource Manager to automatically assign consumer groups to sessions by providing mappings between session attributes and consumer groups.
New plan directives
New resource plan directives let you set idle timeouts, cancel long-running SQL statements, terminate long-running sessions, and restore sessions to their original consumer group at the end of a top call.
Two new resource manager policies have also been added: the
RATIO CPU allocation policy and the
RUN_TO_COMPLETION scheduling policy.
New initialization parameter
RESUMABLE_TIMEOUT initialization parameter lets you enable resumable space allocation and set a timeout period across all sessions.
Tuning by "service and SQL" augments tuning by "session and SQL" in the majority of systems where all sessions are anonymous and shared.
See "Defining Application Services for Oracle Database 10g" and Oracle Database Performance Tuning Guide for more information.
Simplified recovery through resetlogs
The format for archive log file naming, as specified by the
ARCHIVE_LOG_FORMAT initialization parameter, now includes the resetlogs ID, which allows for easier recovery of a database from a previous backup.
Automated shared server configuration and simplified shared server configuration parameters.
You no longer need to preconfigure initialization parameters for shared server. Parameters can be configured dynamically, and most parameters are now limiting parameters to control resources. The recommended method for enabling shared server now is by setting
SHARED_SERVERS initialization parameter, rather than the
DISPATCHERS initialization parameter.
Consolidation of session-specific trace output
For shared server sessions, the
trcsess command-line utility consolidates in one place the trace pertaining to a user session.
Block remote access to restricted instances
Remote access to a restricted instance through an Oracle Net listener is blocked.
Dynamic SGA enhancements
JAVA_POOL_SIZE initialization parameter is now dynamic. There is a new
STREAMS_POOL_SIZE initialization parameter, which is also dynamic. A new view,
V$SGAINFO, provides a consolidated and concise summary of SGA information.
Irreversible database compatibility
In previous releases you were allowed to lower the compatibility setting for your database. Now, when you advance the compatibility of the database with the
COMPATIBLE initialization parameter, you can no longer start the database using a lower compatibility setting, except by doing a point-in-time recovery to a time before the compatibility was advanced.
Flash recovery area
You can create a flash recovery area in your database where Oracle Database can store and manage files related to backup and recovery.
Sorted hash clusters
Sorted hash clusters are new data structures that allow faster retrieval of data for applications where data is consumed in the order in which it was inserted.
Copying Files Using the Database Server
You do not have to use the operating system to copy database files. You can use the
DBMS_FILE_TRANSFER package to copy files.
MAXTRANS physical attribute parameter
MAXTRANS physical attribute parameter for database objects has been deprecated. Oracle Database now automatically allows up to 255 concurrent update transactions for any data block, depending on the available space in the block.
Deprecation of use of rollback segments (manual undo management mode)
Manual undo management mode has been deprecated and is no longer documented in this book. Use an undo tablespace and automatic undo management instead.
Deprecation of the
UNDO_SUPPRESS_ERRORS initialization parameter
When operating in automatic undo management mode, the database now ignores any manual undo management mode SQL statements instead of returning error messages.
Deprecation of the
PARALLEL_AUTOMATIC_TUNING initialization parameter
Oracle Database provides defaults for the parallel execution initialization parameters that are adequate and tuned for most situations. The
PARALLEL_AUTOMATIC_TUNING initialization parameter is now redundant and has been deprecated.
Removal of LogMiner chapter
The chapter on LogMiner has been moved to Oracle Database Utilities
Removal of job queues chapter on using the
DBMS_JOB package to submit jobs has been replaced by Scheduler functionality.