This section describes new features of Oracle Streams for 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 Streams:
Oracle Database 10g Release 2 (10.2) New Features in Streams
Oracle Database 10g Release 1 (10.1) New Features in Streams
The following sections describe the new features in Oracle Streams for Oracle Database 10g Release 2 (10.2):
Oracle Database 10g Release 2 includes performance improvements for most Streams operations. Specifically, the following Streams components have been improved to perform more efficiently and handle greater workloads:
Capture processes
Propagations
Apply processes
This release also includes the following specific performance improvements:
More types of rules are simple rules for faster rule evaluation. See "Simple Rule Conditions".
Declarative rule-based transformations perform transformations more efficiently. See "Declarative Rule-Based Transformations".
Real-time downstream capture reduces the amount of time required for a downstream capture process to capture changes made at the source database. See "Real-Time Downstream Capture".
Enhanced prefiltering during capture process rule evaluation enables capture processes to capture changes in the redo log more efficiently. See "Capture Process Rule Evaluation".
The new ANYDATA_FAST_EVAL_FUNCTION
function in the STREAMS$_EVALUATION_CONTEXT
provides more efficient access to values inside an ANYDATA
object. See "Evaluation Contexts Used in Streams".
The following are Streams configuration manageability enhancements for Oracle Database 10g Release 2:
Supplemental Logging Enabled During Preparation for Instantiation
Configurable Transaction Spill Threshold for Apply Processes
Information About Oldest Transaction in V$STREAMS_APPLY_READER
Automatic Shared Memory Management of the Streams Pool
The Oracle Automatic Shared Memory Management feature manages the size of the Streams pool when the SGA_TARGET
initialization parameter is set to a nonzero value.
See Also:
"Streams Pool"Streams Tool in Oracle Enterprise Manager
The Streams tool in Oracle Enterprise Manager enables you to configure, manage, and monitor a Streams environment using a Web browser.
See Also:
The online help for the Streams tool in Oracle Enterprise Manager
Procedures for Starting and Stopping Propagations
The START_PROPAGATION
and STOP_PROPAGATION
procedures are added to the DBMS_PROPAGATION_ADM
package.
A queue-to-queue propagation always has its own exclusive propagation job to propagate messages from the source queue to the destination queue. Also, in an Oracle Real Application Clusters (RAC) environment, when the destination queue in a queue-to-queue propagation is a buffered queue, the queue-to-queue propagation uses a service for transparent failover to another instance if the primary RAC instance fails.
See Also:
"Queue-to-Queue Propagations"Declarative Rule-Based Transformations
Declarative rule-based transformations provide a simple interface for configuring a set of common transformation scenarios for row LCRs. No user-defined PL/SQL function is required to configure a declarative rule-based transformation.
See Also:
"Declarative Rule-Based Transformations"Commit-time queues provide more control over the order in which user-enqueued messages in a queue are browsed or dequeued.
See Also:
"Commit-Time Queues"Supplemental Logging Enabled During Preparation for Instantiation
The following procedures in the DBMS_CAPTURE_ADM
package now include a supplemental_logging
parameter which controls the supplemental logging specifications for the database objects being prepared for instantiation: PREPARE_TABLE_INSTANTIATION
, PREPARE_SCHEMA_INSTANTIATION
, and PREPARE_GLOBAL_INSTANTIATION
.
Configurable Transaction Spill Threshold for Apply Processes
The new txn_lcr_spill_threshold
apply process parameter enables you to specify that an apply process begins to spill messages for a transaction from memory to disk when the number of messages in memory for a particular transaction exceeds the specified number. The DBA_APPLY_SPILL_TXN
and V$STREAMS_APPLY_READER
views enable you to monitor the number of transactions and messages spilled by an apply process.
Conversion of LCRs to and from XML
The following functions in the DBMS_STREAMS
package convert a logical change record (LCR) to or from XML:
CONVERT_LCR_TO_XML
converts an LCR encapsulated in a ANYDATA
object into an XML object that conforms to the XML schema for LCRs.
CONVERT_XML_TO_LCR
converts an XML object that conforms to the XML schema for LCRs into an LCR encapsulated in a ANYDATA
object.
Retrying an Error Transaction with a User Procedure
A new parameter, user_procedure
, is added to the EXECUTE_ERROR
procedure in the DBMS_APPLY_ADM
package. This parameter enables you to specify a user procedure that modifies one or more LCRs in an error transaction before the transaction is executed.
Enhanced Support for Index-Organized Tables
Streams capture processes and apply processes now support index-organized tables that contain the following datatypes, in addition to the datatypes that were supported in past releases of Oracle:
LONG
LONG
RAW
CLOB
NCLOB
BLOB
BFILE
Logical change records (LCRs) containing these datatypes in index-organized tables can also be propagated using propagations.
Also, Streams now supports index-organized tables that include an OVERFLOW
segment.
Row LCR Execution Enhancements
In previous releases, the EXECUTE
member procedure for row LCRs only execute row LCRs in an apply handler for an apply process. In Oracle Database 10g Release 2, the EXECUTE
member procedure can execute user-constructed row LCRs, row LCRs in the error queue, and row LCRs that were last enqueued by an apply process, user, or application.
See Also:
Information About Oldest Transaction in V$STREAMS_APPLY_READER
The following new columns are added to the V$STREAMS_APPLY_READER
dynamic performance view: OLDEST_XIDUSN
, OLDEST_XIDSLT
, and OLDEST_XIDSQN
. These columns show the transaction identification number of the oldest transaction being assembled or applied by an apply process. The DBA_APPLY_PROGRESS
view also contains this information. However, for a running apply process, the information in the V$STREAMS_APPLY_READER
view is more current than the information in the DBA_APPLY_PROGRESS
view.
See Also:
Oracle Database Reference for more information about theV$STREAMS_APPLY_READER
dynamic performance viewThe following are Streams replication enhancements for Oracle Database 10g Release 2:
Simple Streams Replication Configuration
The following new procedures in the DBMS_STREAMS_ADM
package provide simplify configuration of a Streams replication environment:
MAINTAIN_GLOBAL
configures a Streams environment that replicates changes at the database level between two databases.
MAINTAIN_SCHEMAS
configures a Streams environment that replicates changes to specified schemas between two databases.
MAINTAIN_SIMPLE_TTS
configures a Streams environment that replicates changes to a single, self-contained tablespace between two databases. This procedure replaces the MAINTAIN_SIMPLE_TABLESPACE
procedure.
MAINTAIN_TABLES
configures a Streams environment that replicates changes to specified tables between two databases.
MAINTAIN_TTS
configures a Streams environment that replicates changes to a self-contained set of tablespaces. This procedure replaces the MAINTAIN_TABLESPACES
procedure.
PRE_INSTANTIATION_SETUP
and POST_INSTANTIATION_SETUP
configure a Streams environment that replicates changes at the database level or to specified tablespaces between two databases. These procedures must be used together, and instantiation actions must be performed manually, to complete the Streams replication configuration.
See Also:
LOB assembly simplifies processing of row LCRs with LOB columns in DML handler and error handlers.
Virtual Dependency Definitions
A virtual dependency definition is a description of a dependency that is used by an apply process to detect dependencies between transactions at a destination database. Virtual dependency definitions enable an apply process to detect dependencies that it would not be able to detect by using only the constraint information in the data dictionary.
Instantiation Using Transportable Tablespace from Backup
A new RMAN command, TRANSPORT
TABLESPACE
, enables you to instantiate a set of tablespaces while the tablespaces in the source database remain online. The tablespaces can be added to the destination database using Data Pump import or the ATTACH_TABLESPACES
procedure in the DBMS_STREAMS_TABLESPACE_ADM
package.
RMAN Database Instantiation Across Platforms
The RMAN CONVERT
DATABASE
command can be used to instantiate an entire database in a replication environment where the source and destination databases are running on different platforms that have the same endian format.
Apply Processes Allow Duplicate Rows
In releases prior to Oracle Database 10g Release 2, an apply process always raises an error when it encounters a row LCR that changes more than one row in a table. In Oracle Database 10g Release 2, the new allow_duplicate_rows
apply process parameter can be set to true
to allow an apply process to apply a row LCR that changes more than one row.
View for Monitoring Long Running Transactions
The V$STREAMS_TRANSACTION
dynamic performance view enables monitoring of long running transactions that currently are being processes by Streams capture processes and apply processes.
See Also:
Oracle Database Reference for more information about theV$STREAMS_TRANSACTION
dynamic performance viewIn Oracle Database 10g Release 2, a new procedure, ALTER_EVALUATION_CONTEXT
in the DBMS_RULE_ADM
package, enables you to alter an existing evaluation context.
Information provisioning makes information available when and where it is needed. Oracle Database 10g Release 2 makes it is easier to bulk provision a large amount of information and to incrementally provision information using Streams.
The following sections describe the new features in Oracle Streams for Oracle Database 10g Release 1 (10.1):
Oracle Database 10g Release 1 includes performance improvements for most Streams operations. Specifically, the following Streams components have been improved to perform more efficiently and handle greater workloads:
Capture processes
Propagations
Apply processes
This release also includes performance improvements for ANYDATA
queue operations and rule set evaluations.
The following are Streams configuration manageability enhancements for Oracle Database 10g Release 1:
Ability to Add User-Defined Conditions to System-Created Rules
Simpler Rule-Based Transformation Configuration and Administration
Simpler Removal of Rule Sets When a Streams Client Is Dropped
Streams clients, which include capture processes, propagations, apply processes, and messaging clients, can use two rule sets: a positive rule set and a negative rule set. Negative rule sets make it easier to discard specific changes so that they are not processed by a Streams client.
A capture process can run on a database other than the source database. The redo log files from the source database are copied to the other database, called a downstream database, and the capture process captures changes in these redo log files at the downstream database.
Subset Rules for Capture and Propagation
You can use subset rules for capture processes, propagations, and messaging clients, as well as for apply processes.
See Also:
"Subset Rules"When Streams is used in a single database, memory is allocated from a pool in the System Global Area (SGA) called the Streams pool. The Streams pool contains buffered queues and is used for internal communications during parallel capture and apply. Also, a new dynamic performance view, V$STREAMS_POOL_ADVICE
, provides information that you can use to determine the best size for Streams pool.
Access to Buffered Queue Information
The following new dynamic performance views enable you to monitor buffered queues:
V$BUFFERED_QUEUES
V$BUFFERED_SUBSCRIBERS
V$BUFFERED_PUBLISHERS
The default tablespace for LogMiner has been changed from the SYSTEM
tablespace to the SYSAUX
tablespace. When configuring a new database to run a capture process, you no longer need to relocate the LogMiner tables to a non-SYSTEM
tablespace.
Ability to Add User-Defined Conditions to System-Created Rules
Some of the procedures that create rules in the DBMS_STREAMS_ADM
package include an and_condition
parameter. This parameter enables you to add custom conditions to system-created rules.
Simpler Rule-Based Transformation Configuration and Administration
A new procedure, SET_RULE_TRANSFORM_FUNCTION
in the DBMS_STREAMS_ADM
package, makes it easy to specify and administer rule-based transformations.
Enqueue Destinations Upon Apply
A new procedure, SET_ENQUEUE_DESTINATION
in the DBMS_APPLY_ADM
package, makes it easy to specify a destination queue for messages that satisfy a particular rule. When a message satisfies such a rule in an apply process rule set, the apply process enqueues the message into the specified queue.
Execution Directives Upon Apply
A new procedure, SET_EXECUTE
in the DBMS_APPLY_ADM
package, enables you to specify that apply processes do not execute messages that satisfy a specific rule.
Support for Additional Datatypes
Streams capture processes and apply processes now support the following additional datatypes:
NCLOB
BINARY_FLOAT
BINARY_DOUBLE
LONG
LONG
RAW
Logical change records (LCRs) containing these datatypes can also be propagated using propagations.
See Also:
Support for Index-Organized Tables
Streams capture processes and apply processes now support processing changes to index-organized tables.
You can use a new type of apply handler called a precommit handler to record information about commits processed by an apply process.
See Also:
Better Interoperation with Oracle Real Application Clusters
The following are specific enhancements that improve Streams interoperation with Oracle Real Application Clusters (RAC):
Streams capture processes running in a RAC environment can capture changes in the online redo log as well as the archived redo log.
If the owner instance for a queue table containing a queue used by a capture process or apply process becomes unavailable, then queue ownership is transferred automatically to another instance in the cluster and the capture process or apply process is restarted automatically (if it had been running).
See Also:
Support for Function-Based Indexes and Descending Indexes
Streams capture processes and apply processes now support processing changes to tables that use function-based indexes and descending indexes.
Simpler Removal of Rule Sets When a Streams Client Is Dropped
A new parameter, drop_unused_rule_sets
, is added to the following procedures:
DROP_CAPTURE
in the DBMS_CAPTURE_ADM
package
DROP_PROPAGATION
in the DBMS_PROPAGATION_ADM
package
DROP_APPLY
in the DBMS_APPLY_ADM
package
If you drop a Streams client using one of these procedures and set this parameter to true
, then the procedure drops any rule sets, positive and negative, used by the specified Streams client if these rule sets are not used by any other Streams client. Streams clients include capture processes, propagations, apply processes, and messaging clients. If this procedure drops a rule set, then this procedure also drops any rules in the rule set that are not in another rule set.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the procedures for dropping Streams clients
Simpler Removal of ANYDATA Queues
A new procedure, REMOVE_QUEUE
in the DBMS_STREAMS_ADM
package, enables you to remove an ANYDATA
queue. This procedure also has a cascade
parameter. When cascade
is set to true
, any Stream client that uses the queue is removed also.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the REMOVE_QUEUE procedure
Control Over Data Dictionary Builds in the Redo Log
You can use the BUILD
procedure in the DBMS_CAPTURE_ADM
package to extract the data dictionary of the current database to the redo log. A capture process can use the extracted information in the redo log to create the LogMiner data dictionary for the capture process. This procedure also identifies a valid first system change number (SCN) value that can be used by the capture process. The first SCN for a capture process is the lowest SCN in the redo log from which a capture process can capture changes. In addition, you can reset the first SCN for a capture process to purge unneeded information in a LogMiner data dictionary.
See Also:
Additional Streams Data Dictionary Views and View Columns
This release includes new Streams data dictionary views and new columns in Streams data dictionary views that existed in past releases.
See Also:
Chapter 19, "Monitoring a Streams Environment" for an overview of the Streams data dictionary views and example queries
Oracle Streams Replication Administrator's Guide for example queries that are useful in a Streams replication environment
Copying and Moving Tablespaces
The DBMS_STREAMS_TABLESPACE_ADM
package provides administrative procedures for copying tablespaces between databases and moving tablespaces from one database to another. This package uses transportable tablespaces, Data Pump, and the DBMS_FILE_TRANSFER
package.
Simpler Streams Administrator Configuration
In this release, granting the DBA
role to a Streams administrator is sufficient for most actions performed by the Streams administrator. In addition, a new package, DBMS_STREAMS_AUTH
, provides procedures that make it easy for you to configure and manage a Streams administrator.
See Also:
"Configuring a Streams Administrator"A new procedure, REMOVE_STREAMS_CONFIGURATION
in the DBMS_STREAMS_ADM
package, enables you to remove the entire Streams configuration at a database.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about theREMOVE_STREAMS_CONFIGURATION
procedureThe following are Streams replication enhancements for Oracle Database 10g Release 1:
New Data Dictionary Views for Schema and Global Instantiations
A Generated Script to Migrate from Advanced Replication to Streams
Additional Supplemental Logging Options
For database supplemental logging, you can specify that all FOREIGN
KEY
columns in a database are supplementally logged, or that ALL
columns in a database are supplementally logged. These new options are added to the PRIMARY
KEY
and UNIQUE
options, which were available in past releases.
For table supplemental logging, you can specify the following options for log groups:
PRIMARY
KEY
FOREIGN
KEY
UNIQUE
ALL
These new options make it easier to specify and manage supplemental logging at a source database because you can specify supplemental logging without listing each column in a log group. If a table changes in the future, then the correct columns are logged automatically. For example, if you specify FOREIGN
KEY
for a table's log group, then the foreign key for a row is logged when the row is changed, even if the columns in the foreign key change in the future.
See Also:
Oracle Streams Replication Administrator's Guide for more information about supplemental logging in a Streams replication environmentAdditional Ways to Perform Instantiations
In addition to original export/import, you can use Data Pump export/import, transportable tablespaces, and RMAN to perform Streams instantiations.
See Also:
Oracle Streams Replication Administrator's Guide for more information about performing instantiationsNew Data Dictionary Views for Schema and Global Instantiations
The following new data dictionary views enable you to determine which database objects have a set instantiation SCN at the schema and global level:
DBA_APPLY_INSTANTIATED_SCHEMAS
DBA_APPLY_INSTANTIATED_GLOBAL
Recursively Setting Schema and Global Instantiation SCN
A new recursive
parameter in the SET_SCHEMA_INSTANTIATION_SCN
and SET_GLOBAL_INSTANTIATION_SCN
procedures enables you to set the instantiation SCN for a schema or database, respectively, and for all of the database objects in the schema or database.
See Also:
Oracle Streams Replication Administrator's Guide for more information about performing instantiations
Oracle Database PL/SQL Packages and Types Reference for more information about the SET_SCHEMA_INSTANTIATION_SCN
and SET_GLOBAL_INSTANTIATION_SCN
procedures
Access to Streams Client Information During LCR Processing
The DBMS_STREAMS
package includes two new functions: GET_STREAMS_NAME
and GET_STREAMS_TYPE
. These functions return the name and type, respectively, of a Streams client that is processing an LCR. You can use these functions in rule conditions, rule-based transformations, apply handlers, error handlers, and in a rule condition.
For example, if you use one error handler for multiple apply processes, then you can use the GET_STREAMS_NAME
function to determine the name of the apply process that raised the error. Also, you can use the GET_STREAMS_TYPE
function to instruct a DML handler to operate differently if it is processing messages from the error queue (ERROR_EXECUTION
type) instead of the apply process queue (APPLY
type).
See Also:
"Managing an Error Handler" for an example of an error handler that uses the GET_STREAMS_NAME
function
Oracle Database PL/SQL Packages and Types Reference for more information about these functions
You can use the MAINTAIN_SIMPLE_TABLESPACE
procedure to configure Streams replication for a simple tablespace, and you can use the MAINTAIN_TABLESPACES
procedure to configure Streams replication for a set of self-contained tablespaces. Both of these procedures are in the DBMS_STREAMS_ADM
package. These procedures use transportable tablespaces, Data Pump, the DBMS_STREAMS_TABLESPACE_ADM
package, and the DBMS_FILE_TRANSFER
package to configure the environment.
See Also:
Control Over Comparing Old Values in Conflict Detection
The COMPARE_OLD_VALUES
procedure in the DBMS_APPLY_ADM
package enables you to specify whether to compare old values of one or more columns in a row LCR with the current value of the corresponding columns at the destination database during apply.
You can optionally use the INCLUDE_EXTRA_ATTRIBUTE
procedure in the DBMS_CAPTURE_ADM
package to instruct a capture process to include the following extra attributes in LCRs:
row_id
serial#
session#
thread#
tx_name
username
See Also:
"Extra Information in LCRs"New Procedure for Point-In-Time Recovery in a Streams Environment
The GET_SCN_MAPPING
procedure in the DBMS_STREAMS_ADM
package gets information about the SCN values to use for Streams capture and apply processes to recover transactions after point-in-time recovery is performed on a source database in a multiple-source Streams environment.
New Member Procedures and Functions for LCR Types
You can use the following new member procedures and functions for LCR types:
The GET_COMMIT_SCN
member function returns the commit SCN of the transaction to which the current LCR belongs.
The GET_EXTRA_ATTRIBUTE
member function returns the value for the specified extra attribute in an LCR, and the SET_EXTRA_ATTRIBUTE
member procedure enables you to set the value for the specified extra attribute in an LCR.
The GET_COMPATIBLE
member function returns the minimal database compatibility required to support an LCR.
The CONVERT_LONG_TO_LOB_CHUNK
member procedure converts LONG
data in a row LCR into a CLOB
, or converts LONG
RAW
data in a row LCR into a BLOB
.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about LCR types and the new member procedures and functions
Oracle Streams Replication Administrator's Guide for an example of a DML handler that uses the GET_COMMIT_SCN
member function
"Rule Conditions that Instruct Streams Clients to Discard Unsupported LCRs" for an example of a rule condition that uses the GET_COMPATIBLE
member function
A Generated Script to Migrate from Advanced Replication to Streams
You can use the procedure DBMS_REPCAT.STREAMS_MIGRATION
to generate a SQL*Plus script that migrates an existing Advanced Replication environment to a Streams environment.
See Also:
Oracle Streams Replication Administrator's Guide for information about migrating from Advanced Replication to StreamsThe following are Streams messaging enhancements for Oracle Database 10g Release 1:
Simpler Configuration of Rule-Based Dequeue or Apply of Messages
Simpler Configuration of Rule-Based Propagations of Messages
Simpler Configuration of Message Notifications
See Also:
Oracle Streams Advanced Queuing User's Guide and Reference for more information about Streams messaging enhancementsA messaging client is a new type of Streams client that enables users and applications to dequeue messages from an ANYDATA
queue based on rules. You can create a messaging client by specifying dequeue
for the streams_type
parameter in certain procedures in the DBMS_STREAMS_ADM
package.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_STREAMS_ADM
package
Simpler Enqueue and Dequeue of Messages
A new package, DBMS_STREAMS_MESSAGING
, provides an easy interface for enqueuing messages into and dequeuing messages from an ANYDATA
queue.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_STREAMS_MESSAGING
package
Simpler Configuration of Rule-Based Dequeue or Apply of Messages
A new procedure, ADD_MESSAGE_RULE
in the DBMS_STREAMS_ADM
package, enables you to configure messaging clients and apply processes, and it enables you to create the rules for user-enqueued messages that control the behavior of these messaging clients and apply processes.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the ADD_MESSAGE_RULE
procedure
Simpler Configuration of Rule-Based Propagations of Messages
A new procedure, ADD_MESSAGE_PROPAGATION_RULE
in the DBMS_STREAMS_ADM
package, enables you to configure propagations and create rules for propagations that propagate user-enqueued messages.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about theADD_MESSAGE_PROPAGATION_RULE
procedureSimpler Configuration of Message Notifications
A new procedure, SET_MESSAGE_NOTIFICATION
in the DBMS_STREAMS_ADM
package, enables you to configure message notifications that are sent when a Streams messaging client dequeues messages. The notification can be sent to an email address, a URL, or a PL/SQL procedure.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the SET_MESSAGE_NOTIFICATION
procedure
The following are rules interface enhancements for Oracle Database 10g Release 1:
During rule set evaluation, a client now can specify that evaluation results are sent iteratively, instead of in a complete list at one time. The EVALUATE
procedure in the DBMS_RULE
package includes the following two new parameters that enable you specify that evaluation results are sent iteratively: true_rules_interator
and maybe_rules_iterator
.
In addition, a new procedure in the DBMS_RULE
package, GET_NEXT_HIT
, returns the next rule that evaluated to TRUE
from a true rules iterator, or returns the next rule that evaluated to MAYBE
from a maybe rules iterator. Also, the new CLOSE_ITERATOR
procedure in the DBMS_RULE
package enables you to close an open iterator.
See Also:
Chapter 28, "Rule-Based Application Example" for examples that use iterative evaluation results
Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_RULE
package
New Dynamic Performance Views for Rule Sets and Rule Evaluations
You can use the following new dynamic performance views to monitor rule sets and rule evaluations:
V$RULE_SET_AGGREGATE_STATS
V$RULE_SET
V$RULE
See Also:
Chapter 23, "Monitoring Rules"