2 New Features in 19c Release Updates
This chapter describes the features that are new in Oracle Database 19c Release Updates (RUs).
- Release Update 19.4 Features
- Release Update 19.5 Features
- Release Update 19.6 Features
- Release Update 19.7 Features
- Release Update 19.8 Features
- Release Update 19.9 Features
- Release Update 19.10 Features
- Release Update 19.11 Features
- Release Update 19.12 Features
- Release Update 19.13 Features
- Release Update 19.14 Features
- Release Update 19.15 Features
- Release Update 19.16 Features
- Release Update 19.17 Features
- Release Update 19.18 Features
- Release Update 19.19 Features
- Release Update 19.20 Features
- Release Update 19.21 Features
- Release Update 19.22.0.0 Features
- Release Update 19.23.0.0 Features
Release Update 19.4 Features
There are no new features for the 19.4 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.5 Features
There are no new features for the 19.5 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.6 Features
There are no new features for the 19.6 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.7 Features
Parent topic: New Features in 19c Release Updates
SQL Macros (SQM)
You can create SQL Macros (SQM) to factor out common SQL expressions and statements
into reusable, parameterized constructs that can be used in other SQL statements.
Starting with Oracle Database release 19c, version 19.7, SQL table macros are supported.
SQL table macros are expressions, typically used in a FROM
clause, to
act as a sort of polymorphic (parameterized) view.
SQL macros increase developer productivity, simplify collaborative development, and improve code quality.
Related Topics
Parent topic: Release Update 19.7 Features
Release Update 19.8 Features
Database In-Memory Base Level
Database In-Memory is an option to Enterprise Edition. Database In-Memory now has a new Base Level feature. This allows the use of Database In-Memory with up to a 16GB column store without triggering any license tracking.
This feature allows you to use Database In-Memory without having to license the option. The column store is limited to 16GB when using the Base Level. This helps to show the value of Database In-Memory without having to worry about licensing issues.
Related Topics
Parent topic: Release Update 19.8 Features
CellMemory Level
You can use the CellMemory feature without enabling the IM column store by
setting INMEMORY_FORCE=CELLMEMORY_LEVEL
and
INMEMORY_SIZE=0
.
This feature allows you to use CellMemory without incurring the overhead of enabling the IM column store.
Related Topics
Parent topic: Release Update 19.8 Features
Release Update 19.9 Features
Parent topic: New Features in 19c Release Updates
Oracle Grid Infrastructure SwitchHome
You can use the -switchGridHome
option with
gridSetup.sh
to switch from one Oracle Grid Infrastructure home to
another.
You can use the -switchGridHome
option for patching and upgrading Oracle
Grid Infrastructure. Use the -switchGridHome
option to switch from the
source Oracle Grid Infrastructure home to the patched Oracle Grid Infrastructure home.
All Oracle Clusterware and Oracle Restart services start from the patched Oracle Grid
Infrastructure home automatically.
Parent topic: Release Update 19.9 Features
Support for DBMS_CRYPTO Asymmetric Key Operations
Starting with this release, the DBMS_CRYPTO
PL/SQL package supports
asymmetric key operations, in addition to the existing support for symmetric key
operations.
DBMS_CRYPTO
package:
PKENCRYPT
PKDECRYPT
SIGN
VERIFY
Related Topics
Parent topic: Release Update 19.9 Features
Release Update 19.10 Features
- Ability to Use Multiple Kerberos Principals with a Single Database Client
- DBMS_CLOUD Package
- New Database Initialization Parameters for Database Resident Connection Pooling (DRCP)
- Oracle Blockchain Table
- Oracle Instant Client Support for Linux for ARM
- Support Per-PDB Capture for Oracle Autonomous Database
- Updated Support for Micro Edition Suite (MES) for FIPS 140.2
Parent topic: New Features in 19c Release Updates
Ability to Use Multiple Kerberos Principals with a Single Database Client
Starting with this release, when you configure Kerberos authentication for an Oracle Database client, you can specify multiple Kerberos principals with a single Oracle Database client.
To enable this functionality, you will need to create a separate credential cache for each user in the client and then use the connect string to specify the user.
In previous releases, you were restricted to one Kerberos principal for each Oracle Database client.
Related Topics
Parent topic: Release Update 19.10 Features
DBMS_CLOUD Package
Oracle provides two core mechanisms to work with data in object stores, as part of
the new DBMS_CLOUD
package or manually defining external tables.
Using DBMS_CLOUD
provides benefits and additional
functionality that goes beyond DDL and is fully compatible with Oracle Autonomous
Database. Oracle strongly recommends leveraging the new DBMS_CLOUD
package over manual external table creation.
Related Topics
Parent topic: Release Update 19.10 Features
New Database Initialization Parameters for Database Resident Connection Pooling (DRCP)
New database initialization parameters, MIN_AUTH_SERVERS
and
MAX_AUTH_SERVERS
, have been added to configure Database Resident
Connection Pooling (DRCP).
MIN_AUTH_SERVERS
and MAX_AUTH_SERVERS
allow the number
of processes used to handle session authentication for DRCP to be configured for optimal
usage.
Related Topics
Parent topic: Release Update 19.10 Features
Oracle Blockchain Table
Blockchain tables are append-only tables in which only insert operations are allowed. Deleting rows is either prohibited or restricted based on time. Rows in a blockchain table are made tamper-resistant by special sequencing and chaining algorithms. Users can verify that rows have not been tampered. A hash value that is part of the row metadata is used to chain and validate rows.
Blockchain tables can be used to implement blockchain applications where the participants trust the Oracle Database provider, but want means to verify that their data hasn’t been tampered with. The participants are different database users who trust the Oracle Database provider to maintain a verifiable, tamper-resistant blockchain of transactions. All participants must have privileges to insert data into the blockchain table. The contents of the blockchain table are defined and managed by the application, with a few added metadata fields maintained by Oracle Database. By leveraging a trusted provider with verifiable crypto-secure data management practices, such applications can avoid the distributed consensus requirements. This provides most of the protection of the distributed peer-to-peer blockchains, but with much higher throughput and lower transaction latency compared to peer-to-peer blockchains using distributed consensus.
Related Topics
Parent topic: Release Update 19.10 Features
Oracle Instant Client Support for Linux for ARM
Starting with Oracle Database 19c Release Update (19.10), Oracle Instant Client is available on Linux for ARM (aarch64).
You can install Oracle Instant Client by downloading either the zip files or RPMs from the Oracle Instant Client download page on Oracle Technology Network (OTN).
Related Topics
Parent topic: Release Update 19.10 Features
Support Per-PDB Capture for Oracle Autonomous Database
To securely capture and replicate individual PDB changes to Oracle Autonomous Database, you can now use Oracle GoldenGate to provide per-PDB capture.
You can now provide local user credentials to connect to an individual PDB
in a multitenant architecture Oracle Database, and replicate the data from just that PDB
to an Oracle Autonomous Database. You no longer need to create a common user with access
to all PDBs on the multitenant container database (CDB) to replicate a PDB to an Oracle
Autonomous Database. Instead, you can now provision a local user with a predefined set
of privileges to the source PDB that you want to capture. All LogMiner and Capture
processing takes place only in this PDB, and only data from this specific PDB is
captured and written to the Oracle GoldenGate trail. As part of this feature, the
behavior for V$LOGMNR_CONTENTS
changes, depending on whether you
connect to a PDB, or connect to the CDB$ROOT
.
Related Topics
Parent topic: Release Update 19.10 Features
Updated Support for Micro Edition Suite (MES) for FIPS 140.2
Starting with this release, Oracle Database supports Micro Edition Suite (MES) version 4.5 for FIPS 140.2.
The Micro Edition Suite (MES) version 4.5 updates include four new CVEs in the RSA BSAFE MES library, support for the rules that FIPS 140.2 requires, and access to the updated NZ/ZT library from the Crypto Foundation.
This enhancement enables the Oracle Database FIPS 140.2 configuration to benefit from new features and security improvements available from the latest RSA BSAFE MES library.
Related Topics
Parent topic: Release Update 19.10 Features
Release Update 19.11 Features
- Application Continuity Protection Check
- Immutable Tables
- New Database Initialization Parameter for Database Resident Connection Pooling (DRCP)
- Oracle Fleet Patching and Provisioning Zip Copy Image Transfer
Parent topic: New Features in 19c Release Updates
Application Continuity Protection Check
Application Continuity Protection Check (ACCHK) provides guidance on the level of protection for each application that uses Application Continuity and assists you to increase protection, if required.
ACCHK identifies which application configuration is protected to help you make an informed decision about which configuration to use for maximum protection or how to increase protection level for an application configuration. ACCHK also provides diagnostics for an unsuccessful failover.
Parent topic: Release Update 19.11 Features
Immutable Tables
Immutable tables are insert-only tables in which existing data cannot be modified. Deleting rows is either prohibited or restricted based on the insertion time of the rows.
Immutable tables protect data against unauthorized modification by insiders. This includes database administrators or compromised users who have access to insider credentials. Immutable tables also prevent accidental data modification that may be caused by human error.
Related Topics
Parent topic: Release Update 19.11 Features
New Database Initialization Parameter for Database Resident Connection Pooling (DRCP)
A new database initialization parameter, DRCP_DEDICATED_OPT
, has
been added to configure Database Resident Connection Pooling (DRCP).
With DRCP, when the number of application connections to the broker is less
than the maximum pool size, a "dedicated optimization" makes DRCP behave like dedicated
servers. With this optimization, DRCP tends towards a one-to-one correspondence between
application connections and DRCP server processes even if those processes are not
currently doing database work. Setting DRCP_DEDICATED_OPT
to
NO
turns off the optimization and reduces the tendency of the pool
to grow towards its maximum size until necessary. This helps keep the number of DRCP
server processes small when statement execution concurrency is low, therefore reducing
memory usage on the database host.
Related Topics
Parent topic: Release Update 19.11 Features
Oracle Fleet Patching and Provisioning Zip Copy Image Transfer
Starting with Oracle Grid Infrastructure 19c Release Update (19.11), Oracle FPP enables you to install the gold images without transferring them to the target host. You can make the gold images available as zip files, either on a shared file system (NFS) or target hosts.
The Zip copy image transfer feature avoids errors and timeout for deployments with low bandwidth or high latency networks between the Oracle FPP Server and targets. This enables deployments in different data centers.
Related Topics
Parent topic: Release Update 19.11 Features
Release Update 19.12 Features
Parent topic: New Features in 19c Release Updates
Gradual Database Password Rollover for Applications
Starting with this release update, an application can change its database passwords without an administrator having to schedule downtime.
To accomplish this, a database administrator can associate a profile having a non-zero limit for the PASSWORD_ROLLOVER_TIME
password profile parameter, new with this release, with an application schema. This allows the database password of the application user to be altered while allowing the older password to remain valid for the time specified by the PASSWORD_ROLLOVER_TIME
limit. During the rollover period of time, the application instance can use either the old initial password or the new password to connect to the database server. All intermediate passwords cannot be used. When the rollover time expires, only the new password is allowed.
Before this enhancement, an administrator normally took the application down when the application database password was being rotated. This is because the password update requires changes on both the database and the application side. With the gradual database password rollover enhancement, the application can continue to use the older password until the new password is configured in the application.
In addition to the new clause PASSWORD_ROLLOVER_TIME
in the
CREATE PROFILE
and ALTER PROFILE
statements, the
ALTER USER
statement has a new clause, EXPIRE PASSWORD
ROLLOVER PERIOD
. The ACCOUNT_STATUS
column of the
DBA_USERS
and USER_USERS
data dictionary views
have several new statuses indicating values to indicate rollover status.
Related Topics
Parent topic: Release Update 19.12 Features
Oracle Memory Speed Support for PMEM Devices
Oracle recommends that you use Oracle Database with the Oracle Memory Speed (OMS) file system to fully utilize the potential of persistent memory (PMEM) devices safely in data centers.
With PMEM as the backing device, OMS utilizes a memory-mapped file hosted on an XFS-based, DAX-enabled file system to perform I/O operations. You must export the PMEM device as a file using a DAX-enabled file system, such as XFS.
Related Topics
Parent topic: Release Update 19.12 Features
Release Update 19.13 Features
There are no new features for the 19.13 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.14 Features
There are no new features for the 19.14 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.15 Features
There are no new features for the 19.15 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.16 Features
- Enhancements for Identity and Access Management Integration with Oracle Database Environments
- Oracle Data Guard Redo Decryption for Hybrid Disaster Recovery Configurations
Parent topic: New Features in 19c Release Updates
Enhancements for Identity and Access Management Integration with Oracle Database Environments
Available for Oracle Database release 19.16 are enhancements to the integration of Identity and Access Management (IAM) users with Oracle Database Environments.
- Additional Oracle Database environments: The full list of supported Oracle Database environments is as follows:
- Oracle Autonomous Database on Dedicated Exadata Infrastructure
- Oracle Autonomous Database on Shared Exadata Infrastructure
- Oracle Base Database Service
- Ability to use the IAM user name and password to retrieve an IAM token: Retrieving a token using an IAM user name and password or secure external password store (SEPS) is more secure than using the password verifier method of database access.
Related Topics
Parent topic: Release Update 19.16 Features
Oracle Data Guard Redo Decryption for Hybrid Disaster Recovery Configurations
Available for Oracle Database release 19.16, Oracle Data Guard enables you to decrypt redo operations in hybrid cloud disaster recovery configurations where the Cloud database is encrypted with TDE and the on-premises database is not.
Hybrid disaster recovery is often considered a quick-stepping stone to cloud adoption. By enabling the ability to quickly configure disaster recovery even in cases where on-premises databases might not already be encrypted with TDE, the steps required to configure hybrid disaster recovery environments are reduced while still ensuring that redo data is still encrypted during the transportation process.
To enable this feature, Oracle Database introduces the TABLESPACE_ENCRYPTION
initialization parameter, which enables you to control the automatic encryption of tablespaces in both the primary and standby databases, for on-premises and Oracle Cloud Infrastructure (OCI) environments. For example, an on-premises database can be unencrypted and an OCI database can be encrypted.
Related Topics
Parent topic: Release Update 19.16 Features
Release Update 19.17 Features
There are no new features for the 19.17 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.18 Features
Parent topic: New Features in 19c Release Updates
All Time Zone Files (DST) Included in Release Updates (RUs)
Starting with Oracle Database 19c RU 19.18.0, all available DST patches are installed with the RU, and deployed into the Oracle_home/oracore/zoneinfo
directory. Installing DST patches does not affect database operation. However, installing the patches with the RU makes it easier for you to adjust the timezone version of your database, if you have a requirement to do so. For example, if you are using Transportable Tablespaces, or Full Transportable Export/Import, then you must ensure that your source and target databases are using identical character sets and identical time zone settings. With this change, you can more easily choose to change your destination database to use a different time zone file version than the default.
By default, AutoUpgrade changes the database time zone to the latest available level. If you don’t want the time zone to be upgraded, then you must explicitly set the local parameter timezone_upg
in your AutoUpgrade configuration file to no
. For example:
upg1.timezone_upg=no
If you choose to use an older database time zone file, then set the database environment variable ORA_TZFILE
to the older time zone file. The time zone files are located in Oracle_home/oracore/zoneinfo
. By using the environment variable ORA_TZFILE
, you can override the default of using the highest-numbered time zone file.
Related Topics
Parent topic: Release Update 19.18 Features
Release Update 19.19 Features
There are no new features for the 19.19 release update.
Parent topic: New Features in 19c Release Updates
Release Update 19.20 Features
In-Memory Eligibility Test
Many workloads benefit from Database In-Memory, however some may not. The In-Memory Eligibility Tool determines if a given workload would benefit or not benefit from Database In-Memory and assesses its eligibility for use of this feature. Eligibility is gauged by the percentage of analytical activity in the workload. If you are planning to implement Database In-Memory, you can use this tool to quickly identify and filter out databases that are ineligible - those where analytic activity is low and where you would see no substantive gain from the use of Database In-Memory. You can then focus your Database In-Memory deployment on databases whose workload includes more intense analytic activity and could therefore benefit substantially. The higher the percentage of analytical activity in the workload, the more benefit you gain from Database In-Memory.
Related Topics
Parent topic: Release Update 19.20 Features
Release Update 19.21 Features
- AutoUpgrade Automates Data Guard Operations During Database Upgrade
- AutoUpgrade Automates Steps Required for Oracle RAC Database Upgrade
- AutoUpgrade Automates Upgrade and Conversion of Non-CDB to PDB
- AutoUpgrade Automates Upgrade of a PDB via Unplug-Plug-Upgrade
- AutoUpgrade Release Update (RU) Upgrades
- AutoUpgrade Sets Parallelism Based on System Resources
- AutoUpgrade Supports Upgrades with Keystore Access to Databases Using TDE
- AutoUpgrade Unplug-Plugin Upgrades to Different Systems
- FPP Integration with AutoUpgrade
- Oracle Database Automates Database Upgrades with AutoUpgrade
- REST APIs for AutoUpgrade
Parent topic: New Features in 19c Release Updates
AutoUpgrade Automates Data Guard Operations During Database Upgrade
AutoUpgrade automates the steps necessary to upgrade a database in an Oracle Data Guard configuration. Note that in Oracle Database 19c, Data Guard operations are not fully automated. Oracle only supports upgrading a primary database and shutting down of redo apply to a standby database.
Steps that AutoUpgrade automates includes disabling and re-enabling the Data Guard Broker (if present), and deferring log file transport while the upgrade takes place. Automation of these Oracle Data Guard operations in the context of a database upgrade eliminates the need for manual or scripted steps that you otherwise would have to perform yourself. This in turn makes it easier to automate upgrades of databases in Oracle Data Guard configurations. This feature particularly helps to automate upgrades in high-end environments, where there can be many hundreds of such databases that you upgrade as part of your upgrade project.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Automates Steps Required for Oracle RAC Database Upgrade
AutoUpgrade automates all the steps needed to upgrade an Oracle Real Application Clusters (Oracle RAC) database.
AutoUpgrade automates steps that previously had to be performed
manually or scripted. Steps that AutoUpgrade automates include the
SRVCTL
commands to stop and restart instances on
multiple nodes, handling of CLUSTER_DATABASE
, updating
initialization parameter files, and restarting services, where
appropriate.
This feature reduces the possibility of manual errors and decreases the work needed for DBAs to perform routine maintenance and upgrade activities.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Automates Upgrade and Conversion of Non-CDB to PDB
To simplify upgrades to Oracle Database 21c, AutoUpgrade automates steps to convert a database from a non-CDB to a PDB as part of a database upgrade.
Oracle Database 21c requires multitenant architecture. With this release, you can use AutoUpgrade for non-CDB to PDB upgrades from Oracle Database 12c Release 2 (12.2) and later releases. Using the automation features of AutoUpgrade reduces both the effort required of DBAs for upgrades, and the risk associated with typographical errors in a manual process.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Automates Upgrade of a PDB via Unplug-Plug-Upgrade
AutoUpgrade automates unplugging a PDB from a CDB, plugging it into a higher version CDB, and upgrading the PDB to that new target version.
As part of the process to simplify upgrade, you can upgrade pluggable databases (PDBs) using an unplug/plug, where the upgrade occurs when you plug the PDB into the target release container database (CDB). This feature adds another scenario in which AutoUpgrade can automate the entire database upgrade process.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Release Update (RU) Upgrades
AutoUpgrade supports the option of using AutoUpgrade to perform out-of-place Oracle home Release Update patching.
For an out-of-place patch of Oracle Database using AutoUpgrade, AutoUpgrade moves the source database that you want to patch to a new Oracle Database Oracle home, and then patches the database binaries in that target Oracle home with the Release Update that you select. With this option, you can use AutoUpgrade at any time that you want to move the database to a new Oracle home, either as part of a planned upgrade or as part of a patch plan. In a patch operation, AutoUpgrade performs the patch using the following workflow:
- AutoUpgrade recognizes that the source database and the target Oracle Database are the same base release.
- AutoUpgrade skips the upgrade steps.
- AutoUpgrade patches the target database using the Release Update.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Sets Parallelism Based on System Resources
AutoUpgrade automatically evaluates system resources and makes an intelligent decision as to how many upgrade jobs can run simultaneously.
AutoUpgrade uses the CPU_COUNT
value and system process parameters to determine available system resources, and calibrates both the number of upgrades that can run at a time and the number of parallel threads for each upgrade. Upgrades that exceed a safe threshold are put in a queue so that they can be run as system resources become available.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Supports Upgrades with Keystore Access to Databases Using TDE
AutoUpgrade enhances support for databases that use transparent data encryption (TDE) by enabling keystore generation.
AutoUpgrade now enables you to provide passwords to an external key manager generated and maintained by AutoUpgrade. With this configuration, AutoUpgrade supports unmanned or automated operations of TDE-enabled databases. AutoUpgrade can open the source database keystore without prompting for the keystore password, and enroll the target database into the TDE external keystore for key management, so that the target database can start automatically.
Related Topics
Parent topic: Release Update 19.21 Features
AutoUpgrade Unplug-Plugin Upgrades to Different Systems
You can now use the Oracle Database AutoUpgrade Unplug/Plug method to unplug a PDB from one system and plug into a different system and upgrade.
In earlier releases, AutoUpgrade supported unplug/plug/upgrades on the same server, but it was not possible to unplug a PDB from one server, plug it into a different system, and then upgrade the PDB. With this feature, you can now migrate and upgrade the PDB in a single operation, including migrations to the cloud.
Related Topics
Parent topic: Release Update 19.21 Features
FPP Integration with AutoUpgrade
Fleet Patching and Provisioning (FPP) integration with AutoUpgrade provides a new tool for automating and simplifying Oracle Database Upgrade.
This feature makes Oracle Database AutoUpgrade more flexible, provides better control over the upgrade flow mechanism, and provides better usability by showing progress bar and additional elements. You can upgrade multiple databases in parallel.
Related Topics
Parent topic: Release Update 19.21 Features
Oracle Database Automates Database Upgrades with AutoUpgrade
Oracle Database AutoUpgrade enables you to upgrade one or many databases without human intervention, all with one command, and with a single configuration file.
AutoUpgrade enables you to upgrade one or many Oracle Database instances at the command-line, using a single command and a single configuration file. AutoUpgrade runs the preupgrade tasks, performs automated fix-ups where needed, runs the database upgrade, and finishes by completing post-upgrade tasks. It includes automatic retry and fallback, the option to schedule upgrades for future points in time, and the ability to set, change, or remove initialization parameters as desired. Using AutoUpgrade can save you time and money by enabling you to upgrade hundreds of databases with one command, and avoid the need for high-maintenance upgrade solutions.
Related Topics
Parent topic: Release Update 19.21 Features
REST APIs for AutoUpgrade
To facilitate safe and secure remote use of the AutoUpgrade for Oracle Database upgrades, AutoUpgrade now provides REST APIs (ORDS and OCI).
The Oracle REST Data Services (ORDS) database API is a database management and monitoring REST API embedded into Oracle REST Data Services. The Oracle Cloud Infrastructure (OCI) REST API is enabled by configuring the REST Adapter connection to use the OCI Signature Version 1 security policy. You can now use these features to run AutoUpgrade upgrades remotely over SSH.
Related Topics
Parent topic: Release Update 19.21 Features
Release Update 19.22.0.0 Features
- Enabling Scrambled Dequeues and Dequeue Flow Control
- Enhanced Online DDL Capabilities in the Presence of Supplemental Logging
Parent topic: New Features in 19c Release Updates
Enabling Scrambled Dequeues and Dequeue Flow Control
You can enable or disable the scrambling and flow control feature using the queue level parameter:
- To spread the concurrent dequeuers across different blocks or buffers, enable scrambled dequeues using the following queue parameter:
DBMS_AQADM.SET_QUEUE_PARAMETER('<schema_name>.<queue_name>', 'CQ_SCRAMBLED_DEQ', 1);
To disable scrambled dequeues, use the following queue parameter:
DBMS_AQADM.UNSET_QUEUE_PARAMETER('<schema_name>.<queue_name>', 'CQ_SCRAMBLED_DEQ');
- To internally restrict the number of concurrent sessions that execute the dequeue select for update on a queue, enable dequeue flow control using the following queue parameter:
DBMS_AQADM.SET_QUEUE_PARAMETER('<schema_name>.<queue_name>', 'CQ_DEQ_FLOWCONTROL', N);
Where N is the number of internal dequeue sessions allowed to do the core dequeue work concurrently, which causes waits and contentions. Note that N must be less than the number of actual external dequeue sessions.
To disable dequeue flow control, use the following queue parameter:
DBMS_AQADM.UNSET_QUEUE_PARAMETER('MY_QUEUE', 'CQ_DEQ_FLOWCONTROL');
Using these new parameters, you can now spread concurrent dequeuers across different blocks or buffers to reduce buffer busy waits contention and to avoid row lock contention and buffer busy waits contention.
Parent topic: Release Update 19.22.0.0 Features
Enhanced Online DDL Capabilities in the Presence of Supplemental Logging
Numerous DDL operations were blocking operations when supplemental logging was enabled. You can use the OGG_ONLINE_DDL
initialization parameter to lift this restriction for several previously blocking DDL operations when minimal supplemental logging is enabled. Those commands are namely:
ALTER TABLE ADD COLUMN
ALTER TABLE SET COLUMN UNUSED
ALTER TABLE ADD CONSTRAINT ENABLE NOVALIDATE
ALTER TABLE DROP CONSTRAINT
Non-blocking DDL operations are crucial for mission-critical environments where it is hard to impossible to guarantee an idle time window for blocking DDL operations to succeed. Supplemental logging is a key requirement for GoldenGate replication support, which creates a dilemma for customers to choose between non-blocking DDL or using GoldenGate. Enabling more non-blocking DDL operations in the presence of supplemental logging make such a decision void. Customers benefit from non-blocking DDL operations and GoldenGate.
Related Topics
Parent topic: Release Update 19.22.0.0 Features
Release Update 19.23.0.0 Features
Session Exit on Invalidation
Set SESSION_EXIT_ON_PACKAGE_STATE_ERROR
to true to force a hard session exit when a session's state has been invalidated.
Exiting sessions after state invalidation avoids errors that can occur when applications mishandle invalid state.
Related Topics
Parent topic: Release Update 19.23.0.0 Features