01 02 03 04 05 06Database Outsourcing Experts

Oracle 9i release 1

Administration

Default Temporary TablespaceThe system will automatically allocate new users an appropriate temporary tablespace without you needing to specify it explicitly in the ‘create user’ statement. This is achieved by specifying a pre-created temporary tablespace as default using a new extension of the ‘create tablespace’ and ‘alter tablespace’ commands.

Automatic Undo ManagementIn an e�ort to reduce administration overheads, it is now possible to have the system manage it’s own rollback segments (now known as “undo” segments) by specifying the undo tables-pace and undo management type in the parameter �le. The system-managed undo tablespace is essentially a locally managed tablespace with space managed by a bitmap in the �le header.

Constraint EnhancementsEnhancements to the ‘using index’ clause of ‘create table’ and ‘alter table’ statements means you can specify the creation or use of a speci�c index when dealing with primary keys. You can also prevent indexes from being dropped when dropping constraints.

Database QuiescenceYou place the database in a quiesced state in which only the SYS and SYSTEM users can perform transactions. This basically removes the need to stop the database and restart in restricted mode if you want to perform tasks that could interfere with normal usage.

Database Suspend/ResumeThis feature allows you to suspend database activity by stopping I/O to all data�les and queuing any further I/O requests. When ready, you can then resume database operations and the system will re-activate all pending I/O requests in the order they were queued. This is extremely useful for system backups that involve splitting mirrored disks.

Data�le ManagementNew feature allows for automatic management of data�les when you issue tablespace commands. By specifying a directory location in the init.ora �le (or by an ‘alter system’ command), the system will automatically create and delete data�les in that location as necessary. A new addition to the drop tablespace’ clause (‘drop tablespace…including contents and data�les’) will drop all associated data�les be they automatically or manually managed.

Dynamic SGAThe SGA can now be resized without having to restart the database. By issuing ‘alter system’ commands you can resize the shared pool, large pool, bu�er cache and log bu�er. The bu�er cache can only be dynamically resized if you are using the new DB_CACHE_SIZE parameter. You can also place a limit on the size of the SGA by using the SGA_MAX_SIZE initialisation parameter.

Index Organised TablesCan now create and rebuild secondary indexes online.

More Archiving DestinationsYou can now have 5-10 archive log destinations speci�ed in the parameter �le.

Multiple Block SizeTablespaces can be created with non-standard block sizes (i.e. block sizes other than that speci�ed by the DB_BLOCK_SIZE initialisation parameter). To use this feature you must specify a sub-cache for that block size by using the appropriate DBA_(n)K_CACHE_SIZE initialisation parameter.

On-line Table Rede�nition

01 02 03 04 05 06Database Outsourcing Experts

Oracle 9i release 1

Administration

Resumable Space AllocationThis excellent new feature allows you to resume large transactions that have failed due to some space allocation issue such as an object reaching its max extents or a user quota limit exceeded. Suspended transactions are noted in the alert log but a new trigger type (an ‘after suspend’ trigger) can be used in conjunction with a new PL/SQL package to automatically deal with correctable errors.

The Metadata APIA new PL/SQL package, DBMS_METADATA, allows you to view metadata about a schema object in the form of DDL statements.

Automatic Segment Space AllocationThe locally managed tablespace feature which was introduced in Oracle 8i has now been enhanced so that the system can automatically manage space within segments as well as space within the tablespace. This means that Oracle uses bitmaps to manage space within segments instead of using freelists, the traditional method. This means that you no longer need to tune the PCTUSED, FREELIST and FREELIST GROUPS segment attributes.

Cached Execution PlansOracle 9i stores execution plans for cached cursors in a set of new dynamic performance views. This means you can �nd out a particular execution plan at a particular moment when, for example, performance issues have been noticed.

Cursor SharingBy setting a dynamic parameter, you can tell the system to share SQL cursors for similar statements. This works by internally replacing literals in the statements with bind variables, thus automating what many application designers previously had to do manually.

Database Resource ManagerNew functionality includes: the ability to create an active session pool for concurrent sessions; creation of an ‘undo pool’ to allocate speci�c amounts of undo to certain user groups; prevent execution of operations that will last longer than a prede�ned limit and automatic switching of users between groups according to limits set by the administrator.

Database Time ZoneBy specifying a time zone at database creation, the database can operate in a di�erent time zone to the underlying operating system. Dates and times in transactions can also be resolved to the database time zone when applying data.

Dynamic Job Queue ProcessesThese processes are now spawned dynamically through a single co-ordinating process. This means that only the necessary numbers of job queue processes exist at any one time allowing more e�cient memory usage.

Fine Grained AuditingYou can now audit in much greater detail than before. For example, you can use auditing to determine the nature of the data that someone has selected from a table as well as what operations they performed. This can be done either with triggers or with the help of a new PL/SQL package, DBMS_FGA.

Monitoring Index UsageBy using the ‘alter index … monitoring usage’ statement you can see if a particular index is being used. Usage data is then viewed through the v$object_usage system view.

Multi-tier Materalised ViewsYou can now build updateable materialized views on top of other updateable materialized views. This provides the ability to create complex branched replication environments, e.g. for

01 02 03 04 05 06Database Outsourcing Experts

Oracle 9i release 1

Administration

Net8 and LDAPNet8 now supports an LDAP-Compliant directory service which acts as a central repository for database information, network components, user and corporate policies and preferences, user authentication and security information – thus replacing local client-side and server-side �les. This essentially replaces ONAMES but with the added bene�t of being able to support heterogeneous systems and networks. The process by which Net8 resolves an alias into a connect descriptor using LDAP is called “directory naming”.

Proxy AuthenticationEnables you to authorise a middle-tier server to act on behalf of a client.

Server Parameter File (sp�le)Initially created from a standard text parameter �le, this new binary �le is created and maintained on the machine housing the Oracle software. On-line parameter changes made using ‘alter system’ commands are stored here meaning that such updates can persist across start-up and shutdown. Additionally you can start-up a database from a client by referencing the sp�le in a parameter �le on the client machine.

Time-based Log�le SwitchingBy setting a new ARCHIVE_LAG_TARGET initialisation parameter you can cause log�le switches at timed intervals provided there is redo information within the current archive log.

Application Programming

Java Object PersistanceHas now been implemented: SQLJ object types can be associated with Java classes by using “create type” DDL. This allows both Java and SQL developers to be able to access these objects with ease meaning Java objects in the database can be stored and accessed in a standard way.

Context EnhancementsA new catalog index type (CTXCAT) means that Context search performance features can be used on data that exists in small chunks. New CTXRULE index type has been introduced for document classi�cation applications.

Enterprise Java EngineThe renamed JServer from 8i comes with many new features, including the latest compliant engines for servlets and Java Server Pages; enhanced Corba and EJB support; better JDBC driver integration featuring type inheritance support and a native Java bytecode Accelerator and Memory pro�ler, for deployment performance.

Oracle TextOracle Text is the new name for InterMedia text as it is now a native feature.

SQL and PL/SQL integrationThis has been tightened to improve performance. The overhead of calling PL/SQL procedures from SQL has been reduced.

XML DatatypeThis new type stores XML content as a Character Large Object (CLOB). A number of built-in member functions enable developers to manipulate XML content. Additionally the XML type allows SQL operations on XML content and vice versa.

XML SQL FunctionsTwo new SQL functions have been added. SYS_XMLGEN allows dynamic production of XML documents from SQL select clauses. SYS_XMLAGG can aggregate multiple rowset returns

01 02 03 04 05 06Database Outsourcing Experts

Oracle 9i release 1

Application Programming

ANSI Compliant JoinsIn an e�ort to improve portability by standards compliance, left and right outer join syntax is now available as well as syntax for full outer joins.

Enhanced Unicode SupportThe NCHAR datatype has been reclassi�ed in 9i to be used exclusively for Unicode character sets UTF8 and AL16UTF16. When specifying an NCHAR �eld length, you specify it in charac-ters rather than bytes meaning you do not have to worry about space issues for multibyte character sets. Enhanced interoperability between NCHAR and other datatypes mean you can perform implicit and explicit conversions between the two as for other types.

New Date-Time DatatypesTimezone-aware datatypes can automatically account for timezone di�erences in applica-tions that are deployed globally. Using the time zone rules tables for a given region the time zone o�set for a local time can be calculated, taking into consideration Daylight Savings time adjustments, and then used in further operations.

Scrollable CursorsNew cursor type in which you can move both forwards and backwards through the result set. Can use either absolute row numbers or relative row number o�sets depending on your position in the result set. Additional memory usage enhancements have been included for greater e�ciency.

The LONG APIThis is a new API to help facilitate migrations from LONG to LOB datatypes. Helps ensure existing applications require as few changes as possible.

XML PL/SQL PackageThe DBMS_XMLGEN package allows you to create XML documents from any SQL query by

Backup and Recovery Features

“alter database end backup” commandTakes all data�les out of backup mode in a single command. This new command allows you to script database crash recovery procedures without the need for user intervention.

Flashback QueriesBy setting a new init.ora parameter (and having enough disk space!) you can cause the database to retain redo/undo information for a certain period of time. Then with the help of a new PL/SQL package, DBMS_FLASHBACK, you can retrieve old images of data in the speci�ed timeframe and restore if necessary. Requires that you use the new automatic undo manage-ment feature.

RMAN EnhancementsMany new features have been introduced into the Recovery Manager, of which but a few are:

• Persistent configurations that can be created and applied to any session. This includes automatic channel con�guration.

• Retention policy features that you can use to create a moving “recovery windows” for your database.

• Automatic control �le backup and restore means that you can restore a control �le even of the current control �le and RMAN catalogue are lost.

• Block Media recovery to perform recovery of particular blocks in a data�le whilst that data�le is still online. Comes with a new dynamic view v$_database_block_corruption.

• Enhanced archive log backup features include the ability to switch log �les before backing up the logs to produce a consistent state as you would in a self-scripted backup proce-

01 02 03 04 05 06Database Outsourcing Experts

Oracle 9i release 1

Backup and Recovery Features

Fast Fault RecoveryA new parameter, FAST_START_MTTR_TARGET, allows you to specify an expected mean time to recover. Oracle then automatically uses this value to set dirty bu�er limits and limit the amount of redo generated since the last checkpoint by adjusting the rate at which informa-tion is written.

Log Miner EnhancementsThe Log Miner from 8i has been signi�cantly enhanced to include the ability to view DDL statements, direct path inserts and data dictionary information. In addition extra processing features include the ability to view collections of DML statements as transactions; place complex ‘where clauses’ on the information you are extracting so you can see particular classes of statements and generate SQL redo and undo with primary key information to help the DBA rollback changes.All this is �nished o� with a brand new GUI, the Log Miner Viewer.

Trial RecoveriesYou can now practice applying redo to the database in memory without ever writing the information to disk by using the SQL*Plus “recover…test” command. This means that you can

Business Intelligence

Enhanced Query Rewrite FeaturesQuery rewrite can still be used (with materialized views) when the result set only contains some of the data (e.g. because the BETWEEN clause is being used).

Change Data CaptureNew feature that allows incremental changes from target data sources to be captured and applied to the data warehouse automatically.

Data MiningIncorporates Oracle data mining technology into the database so data, data preparation, model building, and model scoring activities all remain in the database and applications can be built on top. Includes important data mining algorithms. This is an optional extra.

Improved Global Index MaintenanceThe new partition statement clause “update global indexes” causes Oracle to automatically maintain global indexes when table partitions are added/altered or dropped, giving improved e�ciency and availability. Previously, global indexes had to be manually rebuilt when partitions were modi�ed.

Multi-Table InsertsProvides enormous performance bene�ts for large data loads by providing the ability to insert into more than one table with a single SQL statement.

OLAP ServerScalable, high performance OLAP calculation engine.

SQL “merge” CommandCan dynamically decide whether to insert data or update current data during a load, depend-ing on whether a corresponding row already exists in a table.

Summary Advisor WizardA new feature of the Enterprise Manager that provides an interactive environment in which to build and optimise materialized views. Helps you proactively optimise your aggregated data based on information gathered from workloads against the data or based on a hypothetical workload. Makes the most cost-e�ective trade-o�s when recommending the creation of new materialized views and evaluating the performance of existing materialized views.

01 02 03 04 05 06Database Outsourcing Experts

Oracle 9i release 1

Business Intelligence

Bitmap Join IndexesProvide for further performance improvements on join indexes (indexes that can span more than one table), especially in star schemas with fact and dimension tables. In addition, bitmap join indexes can eliminate some of the key iteration and bitmap merge work which is often present in star queries with bitmap indexes on the fact table.

Data Block Pre-fetchingThis entirely transparent feature delays data block reads until multiple rows speci�ed by the underlying index are ready to be accessed and then retrieves multiple data blocks at once, rather than reading a single data block at a time. This provides enormous performance gains for queries that are using indexes whose blocks are poorly clustered as it makes best use of system I/O capacity.

External TableDe�ne external �les as tables in the data dictionary and be able to query them as you would ordinary Oracle tables. This provides for very fast data loads as you can load data from an external �le using an “insert into … select from” statement instead of using SQL*Loader. Also enables easy parallelism of data loads without having to split up the �le to be loaded.

List PartitioningA new partitioning method that allows you to specify discrete values on which to partition your table. Allows unordered and unrelated sets of data to be grouped and organised together according to data models.

New Analytical SQL Functions9i provides a number of new SQL functions to serve the Business Intelligence user including complex percentile calculations, ranks & distributions, new statistics and �rst/last aggregates.

Range and Hash PartitioningCan now partition on all Oracle data types and table types such as IOT’s.

SQL “with” ClauseOptimises query speed by eliminating redundant processing in complex queries. Enables a SELECT statement to de�ne the subquery block at the start of the query, process the block just once, label the results, and then refer to the results multiple times.

Table FunctionsEliminate the need to stage data into physical objects during complex data transformation and load sequences. Using Oracle object types and object tables in PL/SQL, data can be dynamically passed through functions in sequence (known as “pipelining”) and only the end result is inserted into a physical object. This additionally enables parallelism of the process because each stage of the process can run concurrently rather than one stage waiting for the