Changes in This Release for Oracle Database XStream Guide

The following features are new in this release:

• DML conflict handlers

  XStream provides prebuilt DML conflict handlers.

  See "Managing XStream In Conflict Detection and Resolution".

• Support for application containers and application common objects in a multitenant environment

  XStream can replicate changes made to application roots and application PDBs.

  See "XStream Out and a Multitenant Environment" and "XStream In and a Multitenant Environment".

• Improved support for user-defined types

  XStream now supports object types, REFs, and varrays.

  See "Data Types Captured by a Capture Process" and "Data Types Applied by Inbound Servers".

• LCRID versions

  An LCRID is the raw value used to specify the position of an LCR for XStream Out. Starting with Oracle Database 12c Release 2 (12.2.0.1), the LCRID is versioned.

  See "LCRIDs and the Position of LCRs".

• XStream support for different character sets in a multitenant container database (CDB)

  When the character set of the root of a CDB is AL32UTF8, any pluggable database (PDB) in the CDB can use a character set that is different from the root and other PDBs.

• XStream supports long identifiers for database objects

  In this release, identifiers for some database objects can be up to 128 bytes in length. XStream outbound servers can capture changes made to database objects with long identifiers, and XStream inbound servers can apply changes to database objects with long identifiers.

• LCR tracking

  You can track an LCR through a stream using the message_tracking_frequency apply parameter or the SET_MESSAGE_TRACKING procedure in the DBMS_XSTREAM_ADM package.

  See "Changes Are Failing to Reach the Client Application in XStream In".

• New capture process parameters

  The following new capture process parameter is added for XStream Out configurations:

  • annotateddlsize

  See Oracle Database PL/SQL Packages and Types Reference for information about these apply parameters.

• New apply parameters

  The following new apply parameters are added for XStream inbound servers:

  • batchsql_mode

  • cdgranularity

  • message_tracking_frequency

  See Oracle Database PL/SQL Packages and Types Reference for information about these apply parameters.

• View the history of events for XStream components

  The DBA_REPLICATION_PROCESS_EVENTS view displays the history of events for XStream components.

  See "Monitoring the History of Events for XStream Out Components" and "Monitoring the History of Events for XStream In Components".

The following features are new in this release:

• Support for Oracle Multitenant option

  Oracle Multitenant option enables an Oracle database to contain a portable set of schemas, objects, and related structures that appears logically to an application as a separate database. This self-contained collection is called a pluggable database (PDB). A multitenant container database (CDB) contains PDBs. You can configure an XStream Out or XStream In environment that includes CDBs and PDBs.

  See "XStream Out and a Multitenant Environment" and "XStream In and a Multitenant Environment".

• Eager apply of large transactions with XStream In

  As a performance optimization, an XStream inbound server can use eager apply to begin to apply large transactions before it receives the commit logical change record (LCR).

  See "Optimizing XStream In Performance for Large Transactions".

• Ability to eliminate apply progress tables with XStream In

  You can configure XStream In to use the redo log to track its progress instead of an apply progress table to avoid potential bottlenecks in transaction processing.

  See "Avoiding Potential Bottlenecks in Transaction Tracking".

• Optimized transaction apply scheduling with XStream In

  When the constraints on the target tables match the constraints on the source tables, you can optimize dependency computation by setting the compute_lcr_dep_on_arrival apply parameter for an inbound server to Y.

  See "Optimizing Transaction Apply Scheduling".

• New apply parameters

  The following new apply parameters are added for XStream outbound servers:

  • excludetag

  • excludetrans

  • excludeuser

  • excludeuserid

  • getapplops

  • getreplicates

  The following new apply parameters are added for XStream inbound servers:

  • compute_lcr_dep_on_arrival

  • eager_size

  • enable_xstream_table_stats

  • handlecollisions

  • max_parallelism

  • optimize_progress_table

  • optimize_self_updates

  • suppresstriggers

  See Oracle Database PL/SQL Packages and Types Reference for information about these apply parameters.

• New capture process parameters

  The following new capture process parameters are added for XStream Out configurations:

  • excludetag

  • include_objects

  • inline_lob_optimization

  • use_rac_service

  See Oracle Database PL/SQL Packages and Types Reference for information about these apply parameters.

• Trusted and untrusted security models

  You can implement the XStream security model that best fits with your organization's requirements.

  See "XStream Security Models".

• Support for the increased size limit for VARCHAR2, NVARCHAR2, and RAW data types

  XStream Out and XStream In support the increased size limit for the VARCHAR2, NVARCHAR2, and RAW data types.

  See "Data Types Captured by a Capture Process" and "Data Types Applied by Inbound Servers".

• Support for XMLType stored object relationally or as binary XML

  XStream Out and XStream In support XMLType stored object relationally or as binary XML.

  See "Data Types Captured by a Capture Process" and "Data Types Applied by Inbound Servers".

• Support SecureFiles LOB columns stored using Advanced LOB Deduplication

  XStream supports changes to SecureFiles LOB columns stored using Advanced LOB Deduplication.

• HTML reports generated by the UTL_SPADV package

  The SHOW_STATS_HTML procedure in the UTL_SPADV package generates HTML output that includes the statistics gathered by the COLLECT_STATS and START_MONITORING procedures in the same package.

  See "The UTL_SPADV Package" and Oracle Database PL/SQL Packages and Types Reference.