Changes in This Release for Oracle Database Administrator's Guide

There are changes in this document for recent releases of Oracle Database.

Changes in Oracle Database 18c

The following are changes in Oracle Database Administrator's Guide for Oracle Database 18c:

New Features

The following features are new in this release:

  • Shadow lost write protection

    Shadow lost write protection provides fast detection and immediate response to a lost write. Using shadow lost write protection can minimize data loss and the time required to repair a database. You can enable shadow lost write protection for a database, a tablespace, or a data file without requiring an Oracle Data Guard standby database.

    See "Managing Lost Write Protection with Shadow Tablespaces".

  • New default location for Oracle Database password file

    The default location for Oracle Database password file is ORACLE_BASE directory instead of ORACLE_HOME directory. This change supports read-only Oracle homes.

    See "ORAPWD Syntax and Command Line Argument Descriptions".

    See "About Configuring an Oracle Home in Read-Only Mode".

  • Private temporary tables

    Private temporary tables are stored in memory and each one is visible only to the session that created it.

    See "Creating a Temporary Table".

  • Inline external tables

    Inline external tables enable the runtime definition of an external table as part of a SQL statement, without creating the external table as persistent object in the data dictionary.

    See "Using Inline External Tables".

  • Parallel queue timeout

    You can specify the action to be taken on a timed out parallel SQL statement by setting the PQ_TIMEOUT_ACTION resource manager directive.

    See "Parallel Queue Timeout".

  • Cancelling a SQL statement in a session

    You can cancel a SQL statement in a session using the ALTER SYSTEM CANCEL SQL statement.

    See "Cancelling a SQL Statement in a Session".

  • Scalable sequence

    A scalable sequence can be used to improve the performance of data load operation in Oracle RAC databases.

    See "Making a Sequence Scalable".

  • Resetting a sequence

    The new RESTART clause can be used in an ALTER SEQUENCE statement to reset a sequence number to a specific value.

    See "Altering Sequences".

  • The Memoptimized Rowstore

    The Memoptimized Rowstore enables fast lookup of data for the tables that are mainly queried based on primary key columns. This feature is particularly useful for the applications such as Internet of Things (IoT).

    See "Improving Query Performance with the Memoptimized Rowstore".

  • Read-only Oracle home

    An Oracle home can be configured in a read-only mode, thus preventing creation or modification of files inside the Oracle home directory ORACLE_HOME. A read-only Oracle home can be used as a software image that can be shared across multiple database servers. This simplifies patching and mass rollout as only one Oracle home image needs to be updated to distribute a patch to multiple database servers.

    See "About Configuring an Oracle Home in Read-Only Mode".

  • Cloning a multitenant pluggable database (PDB) with Oracle Automatic Storage Management (Oracle ASM)

    Oracle ASM can be used to create a clone of a PDB.

    See Oracle Multitenant Administrator's Guide.

  • Proxy resident connection pooling

    Proxy resident connection pooling provides improved high availability, security, and performance for database clients. Proxy resident connection pooling uses the Proxy Resident Connection Pool that can be configured using Oracle Connection Manager in Traffic Director Mode.

    See "About Proxy Resident Connection Pooling".

  • Integration of Microsoft Active Directory Services with Oracle Database

    The Oracle Database can connect directly to Microsoft Active Directory and authenticate and authorize users. This provides a simpler, less complex option than the full featured integration with Oracle Enterprise User Security (EUS) and an Oracle Directory Service.

    See "About Centralized User and Privilege Management".

  • New nologging clauses for Active Data Guard

    Database nologging has been extended to provide better support for use in an Active Data Guard environment without significantly increasing the amount of redo log generation. The following two new nologging modes are introduced as alternatives to the existing nologging mode NOLOGGING:


    See "Performance Considerations of FORCE LOGGING Mode".

  • New features in DBCA silent mode

    • Creating a copy of a multitenant container database (CDB)

      A copy of a CDB can be created using the -createDuplicateDB command.

      See "createDuplicateDB".

    • Creating a copy of an Oracle RAC database

      A copy of an Oracle RAC database can be created using the -createDuplicateDB command option -databaseConfigType with the value of RAC or RACONENODE.

      See "createDuplicateDB".

    • Creating a standby database from an existing database

      A standby database can be created from an existing database using the -createDuplicateDB command option -createAsStandby.

      See "createDuplicateDB".

    • Verifying hardware and software prerequisites before creating a database

      Hardware and software prerequisites for creating a database can be verified by executing the -executePrereqs command on the system where the database needs to be created.

      See "executePrereqs".

    • Creating a copy of a database template

      A copy of a database template can be created using the -createTemplateFromTemplate command.

      See "createTemplateFromTemplate".

  • Creating a copy of a pluggable database (PDB)

    A copy of a PDB can be created using the -createPluggableDatabase command option -createPDBFrom with the value of PDB.

    See "createPluggableDatabase".

Other Changes

The following are additional changes in the release:

Changes in Oracle Database 12c Release 2 (12.2)

The following are changes in Oracle Database Administrator's Guide for Oracle Database 12c Release 2 (12.2).

New Features

The following features are new in this release:

  • Improvements to online redefinition of tables:

    • In past releases, tables with BFILE columns could not be redefined online. In Oracle Database 12c Release 2 (12.2), tables with BFILE columns can be redefined online.

    • For online table redefinition that did not change the shape of the table, you can enable rollback of a table to return the table to its original definition and preserve DML changes made to the table.

      See "Rolling Back Online Table Redefinition".

    • You can refresh dependent fast refreshable materialized views during online table redefinition by setting the refresh_dep_mviews parameter to Y in the REDEF_TABLE procedure or the START_REDEF_TABLE procedure.

      See "Refreshing Dependent Materialized Views During Online Table Redefinition".

    • Optimize the performance of bulk updates to a table with the EXECUTE_UPDATE procedure in the DBMS_REDEFINITION package. Performance is optimized because the updates are not logged in the redo log.

      See "Optimizing the Performance of Bulk Updates".

    • You can query the V$ONLINE_REDEF view to monitor the progress of an online table redefinition operation.

      See "Monitoring Online Table Redefinition Progress".

    • When online table redefinition fails, often you can correct the problem that caused the failure and restart the online redefinition process where it last stopped.

      See "Restarting Online Table Redefinition After a Failure".

  • Limit PGA usage with Resource Manager

    Resource Manager can limit the amount of PGA memory that can be allocated to each session in a particular consumer group.

    See "Program Global Area (PGA)".

  • Improvements in index compression

    You can specify a high level of advanced index compression in addition to the low level available in past releases. The high level of advanced index compression saves more space than the low level.

    See "Creating an Index Using Advanced Index Compression".

  • Hybrid Columnar Compression can be enabled for array inserts

    Rows inserted with an array insert can be compressed using Hybrid Columnar Compression. In past releases, only rows inserted with a direct-path INSERT could be compressed using Hybrid Columnar Compression.

    See "About Table Compression".

  • Improvements in table move operations

    When the ONLINE keyword is included in an ALTER TABLE MOVE statement, data manipulation language (DML) operations are supported during the move operation. Also, indexes are usable during the move operation when the ONLINE keyword is included and the UPDATE INDEXES clause is included.

    See "About Moving a Table to a New Segment or Tablespace".

  • New SYSRAC administrative privileges for separation of duties

    Oracle Database now provides an new administrative privilege for tasks related to Oracle Real Application Clusters (Oracle RAC) operations.

    See "Administrative Privileges".

  • New database resident connection pooling parameter for long running transactions

    To prevent long running transactions from being rolled back because of the limit specified in the MAX_THINK_TIME parameter, the new parameter MAX_TXN_THINK_TIME for subprograms in the DBMS_CONNECTION_POOL package specifies the maximum amount of time, in seconds, for any sessions with a transaction in progress.

    See "Configuration Parameters for Database Resident Connection Pooling".

  • Additional information available about the state of each connection in the database resident connection pool

    New columns added to the V$CPOOL_CONN_INFO view provide more information about the current state of each connection in the connection pool.

    See "Determining the States of Connections in the Connection Pool".

  • Improved monitoring for database links

    New views and supplied PL/SQL functions enable you to determine the host name of an outgoing database link, view detailed information about information about incoming database links, and determine the source of high system change number (SCN) activity for incoming database links.

    See "Determining the Host of Outgoing Database Links", "Determining Information About Incoming Database Links", and "Determining the Source of High SCN Activity for Incoming Database Links".

  • Object quarantine

    Object quarantine isolates an object that has raised an error and monitors the object for impacts on the system.

    See "Monitoring Quarantined Objects".

  • Delay of instance abort

    The INSTANCE_ABORT_DELAY_TIME initialization parameter specifies a delay time when an error causes an instance to abort.

    See "Delaying Instance Abort".

  • Prespawned processes

    Oracle Database can prespawn processes for better client connection performance.

    See "Managing Prespawned Processes".

  • Partitioned external tables

    For large amounts of data, partitioning for external tables provides fast query performance and enhanced data maintenance.

    See "Partitioning External Tables".

Changes in Oracle Database 12c Release 1 (

The following are changes in Oracle Database Administrator's Guide for Oracle Database 12c Release 1 (

New Features

The following features are new in this release:

  • In-Memory Column Store

    The In-Memory Column Store (IM column store) in an optional area in the SGA that stores whole tables, table partitions, individual columns, and materialized views in a compressed columnar format. The database uses special techniques to scan columnar data extremely rapidly. The IM column store is a supplement to rather than a replacement for the database buffer cache.

    See "Improving Query Performance with Oracle Database In-Memory".

  • Data Pump Support for the In-Memory Column Store

    Data Pump can keep, override, or drop the In-Memory clause for database objects being imported.

    See Oracle Database In-Memory Guide.

  • Force full database caching mode

    To improve performance, you can force an instance to store the database in the buffer cache.

    See "Using Force Full Database Caching Mode".

  • Big Table Cache

    The Automatic Big Table Caching feature enables parallel queries to use the buffer cache.

    See "Memory Architecture Overview".

  • Attribute-clustered tables

    Attribute clustering specifies a directive for heap-organized tables to store data in close proximity on disk, providing performance and data storage benefits. This directive is only applicable for direct path operations, such was a bulk insert or a move operation.

    See "Consider Using Attribute-Clustered Tables".

  • Zone maps

    A zone is a set of contiguous data blocks on disk. A zone map tracks the minimum and maximum of specified columns for all individual zones. The primary benefit of zone maps is I/O reduction for table scans.

    See "Consider Using Zone Maps".

  • Advanced index compression

    Advanced index compression results in excellent compression ratios while still providing efficient access to the indexes. Advanced index compression works at the block level to provide the best compression for each block, which means that users do not require knowledge of data characteristics. Advanced index compression automatically chooses the right compression for each block.

    See "Creating an Index Using Advanced Index Compression".

  • Oracle Clusterware support for the Diagnosability Framework

    Oracle Clusterware uses the Diagnosability Framework and ADR for recording diagnostic trace data and the Clusterware alert log.

    See "ADR in an Oracle Clusterware Environment".

  • READ object privilege and READ ANY TABLE system privilege

    READ privilege on an object enables a user to select from an object without providing the user with any other privileges.

    See "System and Object Privileges for External Tables" and Oracle Database Security Guide for more information.

Changes in Oracle Database 12c Release 1 (

The following are changes in Oracle Database Administrator's Guide for Oracle Database 12c Release 1 (

New Features

The following features are new in this release:

  • Full transportable export/import

    Full transportable export/import enables you to move a database from one database instance to another. Transporting a database is much faster than other methods that move a database, such as full database export/import. In addition, you can use full transportable export/import to move a non-CDB (or an Oracle Database 11g Release 2 ( database) into a PDB that is part of a CDB.

    See Transporting Data.

  • New administrative privileges for separation of duties

    Oracle Database now provides administrative privileges for tasks related to Oracle Recovery Manager (Oracle RMAN), Oracle Data Guard, and Transparent Data Encryption. Each new administrative privilege grants the minimum required privileges to complete tasks in each area of administration. The new administrative privileges enable you to avoid granting SYSDBA administrative privilege for many common tasks.

    See "Administrative Privileges"

  • Database Smart Flash Cache support for multiple flash devices

    A database instance can access and combine multiple flash devices for Database Smart Flash Cache without requiring a volume manager.

    See "Database Smart Flash Cache Initialization Parameters".

  • Temporary undo

    Undo for temporary objects is stored in a temporary tablespace, not in the undo tablespace. Using temporary undo reduces the amount of undo stored in the undo tablespace and the size of the redo log. It also enables data manipulation language (DML) operations on temporary tables in a physical standby database with the Oracle Active Data Guard option.

    See "Managing Temporary Undo". Also, see Oracle Data Guard Concepts and Administration for information about the benefits of temporary undo in an Oracle Data Guard environment.

  • Move a data file online

    You can move a data file when the data file is online and being accessed. This capability simplifies maintenance operations, such as moving data to a different storage device.

    See "Renaming and Relocating Online Data Files".

  • Multiple indexes on the same set of columns

    You can create multiple indexes on the same set of columns to perform application migrations without dropping an existing index and recreating it with different attributes.

    See "Understand When to Create Multiple Indexes on the Same Set of Columns".

  • Move a partition or subpartition online

    DML operations can continue to run uninterrupted on a partition or subpartition that is being moved without using online table redefinition.

    See "Moving a Table to a New Segment or Tablespace".

  • Online redefinition of a table in one step

    You can use the REDEF_TABLE procedure in the DBMS_REDEFINITION package to perform online redefinition of a table's storage properties in a single call to the procedure.

    See "Performing Online Redefinition with the REDEF_TABLE Procedure".

  • Online redefinition of tables with multiple partitions

    To minimize downtime when redefining multiple partitions in a table, you can redefine these partitions online in a single session.

    See "Online Redefinition of One or More Partitions".

  • Online redefinition of tables with Virtual Private Database (VPD) policies

    To minimize downtime, tables with VPD policies can be redefined online.

    See "Handling Virtual Private Database (VPD) Policies During Online Redefinition".

  • New time limit parameter in the FINISH_REDEF_TABLE procedure

    The dml_lock_timeout parameter in the FINISH_REDEF_TABLE procedure in the DBMS_REDEFINITION package can specify how long the procedure waits for pending DML to commit.

    See step 8 in "Performing Online Redefinition with Multiple Procedures in DBMS_REDEFINITION".

  • Invisible columns

    You can make individual table columns invisible. Any generic access of a table does not show the invisible columns in the table.

    See "Understand Invisible Columns".

  • Optimized ALTER TABLE...ADD COLUMN with default value for nullable columns

    A nullable column is a column created without using the NOT NULL constraint. For certain types of tables, when adding a nullable column that has a default value, the database can optimize the resource usage and storage requirements for the operation. It does so by storing the default value for the new column as table metadata, avoiding the need to store the value in all existing records.

    See "Adding Table Columns".

  • Copy-on-write cloning of a database with CloneDB

    When cloning a database with CloneDB, Oracle Database can create the files in a CloneDB database based on copy-on-write technology, so that only the blocks that are modified in the CloneDB database require additional storage on disk.

    See "Cloning a Database with CloneDB".

  • DDL log

    When the logging of DDL statements is enabled, DDL statements are recorded in a separate DDL log instead of the alert log.

    See "DDL Log".

  • Debug log

    Some information that can be used to debug a problem is recorded in a separate debug log instead of the alert log.

    See "Debug Log".

  • Full-word options for the Server Control (SRVCTL) utility

    For improved usability, each SRVCTL utility option is a full word instead of single letter.

    See "SRVCTL Command Reference for Oracle Restart".

  • Transaction Guard and Application Continuity

    Transaction Guard ensures at-most-once execution of transactions to protect applications from duplicate transaction submissions and associated logical errors. Transaction Guard enables Application Continuity, which is the ability to replay transactions and continue processing after recoverable communication errors.

    See "Transaction Guard and Application Continuity".

  • Enhanced statement queuing

    Critical statements can bypass the parallel statement queue. You can set the resource plan directive PARALLEL_STMT_CRITICAL to BYPASS_QUEUE for a high-priority consumer group so that parallel statements from the consumer group bypass the parallel statement queue.

    See "Creating Resource Plan Directives ".

  • New Job Types

    Several new script jobs have been added that permit running custom user scripts using SQL*Plus, the RMAN interpreter, or a command shell for the computer platform.

    See "Script Jobs".

Deprecated Features

The following features are deprecated in this release and may be desupported in a future release:

  • The IGNORECASE argument of ORAPWD

    To support strong authentication, Oracle recommends that you set IGNORECASE to n or omit IGNORECASE entirely. The default value of this optional ORAPWD argument is n.

    See "Creating a Database Password File with ORAPWD" for further information.

  • Single-character options with Server Control (SRVCTL) utility commands

    All SRVCTL commands have been enhanced to accept full-word options instead of the single-letter options. All new SRVCTL command options added in this release support full-word options only and do not have single-letter equivalents. The use of single-character options with SRVCTL commands might be desupported in a future release.

    See "SRVCTL Command Reference for Oracle Restart" for further information.

  • The FILE_MAPPING initialization parameter

    The FILE_MAPPING initialization parameter is deprecated. It is still supported for backward compatibility.

    See Oracle Database Reference for information about the FILE_MAPPING initialization parameter.


    This view continues to be available for backward compatibility.

    See "Specifying Scheduler Job Credentials" for further information.