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Oracle® Streams Concepts and Administration
11g Release 1 (11.1)

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1 Introduction to Oracle Streams

This chapter briefly describes the basic concepts and terminology related to Oracle Streams. These concepts are described in more detail in other chapters in this book and in the Oracle Streams Replication Administrator's Guide.

This chapter contains these topics:

Overview of Oracle Streams

Oracle Streams enables information sharing. Using Oracle Streams, each unit of shared information is called a message, and you can share these messages in a stream. The stream can propagate information within a database or from one database to another. The stream routes specified information to specified destinations. The result is a feature that provides greater functionality and flexibility than traditional solutions for capturing and managing messages, and sharing the messages with other databases and applications. Oracle Streams provides the capabilities needed to build and operate distributed enterprises and applications, data warehouses, and high availability solutions. You can use all of the capabilities of Oracle Streams at the same time. If your needs change, then you can implement a new capability of Oracle Streams without sacrificing existing capabilities.

Using Oracle Streams, you control what information is put into a stream, how the stream flows or is routed from database to database, what happens to messages in the stream as they flow into each database, and how the stream terminates. By configuring specific capabilities of Oracle Streams, you can address specific requirements. Based on your specifications, Oracle Streams can capture, stage, and manage messages in the database automatically, including, but not limited to, data manipulation language (DML) changes and data definition language (DDL) changes. You can also put user-defined messages into a stream, and Oracle Streams can propagate the information to other databases or applications automatically. When messages reach a destination, Oracle Streams can consume them based on your specifications.

Figure 1-1 shows the Oracle Streams information flow.

Figure 1-1 Oracle Streams Information Flow

Description of Figure 1-1 follows
Description of "Figure 1-1 Oracle Streams Information Flow"

What Can Oracle Streams Do?

The following sections provide an overview of what Oracle Streams can do:

Capture Messages at a Database

Oracle Streams provides two ways to capture database changes implicitly: capture processes and synchronous captures. A capture process can capture DML changes made to tables, schemas, or an entire database, as well as DDL changes. A synchronous capture can capture DML changes made to tables. Rules determine which changes are captured by a capture process or synchronous capture.

Database changes are recorded in the redo log for the database. A capture process captures changes from the redo log and formats each captured change into a message called a logical change record (LCR). The messages captured by a capture process are called captured LCRs.

A synchronous capture uses an internal mechanism to capture changes and format each captured change into an LCR. The messages captured by a synchronous capture are called persistent LCRs.

The rules used by a capture process or a synchronous capture determine which changes it captures. When changes are captured by a capture process, the database where changes are generated in the redo log is the source database. When changes are captured by a synchronous capture, the database where the synchronous capture is configured is the source database.

A capture process can capture changes locally at the source database, or it can capture changes remotely at a downstream database. A synchronous capture can only capture changes locally at the source database. Both a capture process and a synchronous capture enqueue logical change records (LCRs) into a queue. When a capture process or a synchronous capture captures changes, it is referred to as implicit capture.

Users and applications can also enqueue messages manually. These messages can be LCRs, or they can be messages of a user-defined type called user messages. When users and applications enqueue messages manually, it is referred to as explicit capture.

Stage Messages in a Queue

Messages are stored (or staged) in a queue. These messages can be logical change records (LCRs) or user messages. Capture processes and synchronous captures enqueue messages into an ANYDATA queue, which can stage messages of different types. Users and applications can enqueue messages into an ANYDATA queue or into a typed queue. A typed queue can stage messages of one specific type only.

Propagate Messages from One Queue to Another

Oracle Streams propagations can propagate messages from one queue to another. These queues can be in the same database or in different databases. Rules determine which messages are propagated by a propagation.

Oracle Streams enables you to configure an environment in which changes are shared through directed networks. In a directed network, propagated messages pass through one or more intermediate databases before arriving at a destination database where they are consumed. The messages might or might not be consumed at an intermediate database in addition to the destination database. Using Oracle Streams, you can choose which messages are propagated to each destination database, and you can specify the route messages will traverse on their way to a destination database.

Consume Messages

A message is consumed when it is dequeued from a queue. An apply process can dequeue messages implicitly. A user, application, or messaging client can dequeue messages explicitly. The database where messages are consumed is called the destination database. In some configurations, the source database and the destination database can be the same.

Rules determine which messages are dequeued and processed by an apply process. An apply process can apply messages directly to database objects or pass messages to custom PL/SQL subprograms for processing.

Rules determine which messages are dequeued by a messaging client. A messaging client dequeues messages when it is invoked by an application or a user.

Detect and Resolve Conflicts

An apply process detects conflicts automatically when directly applying LCRs in a replication environment. A conflict is a mismatch between the old values in an LCR and the expected data in a table. Typically, a conflict results when the same row in the source database and destination database is changed at approximately the same time.

When a conflict occurs, you need a mechanism to ensure that the conflict is resolved in accordance with your business rules. Oracle Streams offers a variety of prebuilt conflict handlers. Using these prebuilt handlers, you can define a conflict resolution system for each of your databases that resolves conflicts in accordance with your business rules. If you have a unique situation that prebuilt conflict resolution handlers cannot resolve, then you can build your own conflict resolution handlers.

If a conflict is not resolved, or if a handler procedure raises an error, then all messages in the transaction that raised the error are saved in the error queue for later analysis and possible reexecution.

Transform Messages

A rule-based transformation is any modification to a message that results when a rule in a positive rule set evaluates to TRUE. There are two types of rule-based transformations: declarative and custom.

Declarative rule-based transformations cover a set of common transformation scenarios for row LCRs, including renaming a schema, renaming a table, adding a column, renaming a column, and deleting a column. You specify (or declare) such a transformation using a procedure in the DBMS_STREAMS_ADM package. Oracle Streams performs declarative transformations internally, without invoking PL/SQL.

A custom rule-based transformation requires a user-defined PL/SQL function to perform the transformation. Oracle Streams invokes the PL/SQL function to perform the transformation. A custom rule-based transformation can modify either LCRs or user messages. For example, a custom rule-based transformation can change the data type of a particular column in an LCR.

Either type of rule-based transformation can occur at the following times:

  • During enqueue of a message by a capture process, which can be useful for formatting a message in a manner appropriate for all destination databases

  • During propagation of a message, which can be useful for transforming a message before it is sent to a specific remote site

  • During dequeue of a message by an apply process or messaging client, which can be useful for formatting a message in a manner appropriate for a specific destination database

When a transformation is performed during apply, an apply process can apply the transformed message directly or send the transformed message to an apply handler for processing.

Note:

  • A rule must be in a positive rule set for its rule-based transformation to be invoked. A rule-based transformation specified for a rule in a negative rule set is ignored by capture processes, propagations, apply processes, and messaging clients.

  • Throughout this document, "rule-based transformation" is used when the text applies to both declarative and custom rule-based transformations. This document distinguishes between the two types of rule-based transformations when necessary.

Track Messages With Oracle Streams Tags

Every redo entry in the redo log has a tag associated with it. The data type of the tag is RAW. By default, when a user or application generates redo entries, the value of the tag is NULL for each redo entry, and a NULL tag consumes no space in the redo entry. The size limit for a tag value is 2000 bytes.

In Oracle Streams, rules can have conditions relating to tag values to control the behavior of Oracle Streams clients. For example, a tag can be used to determine whether an LCR contains a change that originated in the local database or at a different database, so that you can avoid change cycling (sending an LCR back to the database where it originated). Also, a tag can be used to specify the set of destination databases for each LCR. Tags can be used for other LCR tracking purposes as well.

You can specify Oracle Streams tags for redo entries generated by a certain session or by an apply process. These tags then become part of the LCRs captured by a capture process or synchronous capture. Typically, tags are used in Oracle Streams replication environments, but you can use them whenever it is necessary to track database changes and LCRs.

Share Information With Non-Oracle Databases

In addition to information sharing between Oracle databases, Oracle Streams supports heterogeneous information sharing between Oracle databases and non-Oracle databases.

What Are the Uses of Oracle Streams?

The following topics briefly describe some of the reasons for using Oracle Streams:

In some cases, Oracle Streams components provide an infrastructure for various features of Oracle.

Data Replication

Oracle Streams can capture data manipulation language (DML) and data definition language (DDL) changes made to database objects and replicate those changes to one or more other databases. An Oracle Streams capture process or synchronous capture captures changes made to source database objects and formats them into LCRs, which can be propagated to destination databases and then applied by Oracle Streams apply processes.

The destination databases can allow DML and DDL changes to the same database objects, and these changes might or might not be propagated to the other databases in the environment. In other words, you can configure an Oracle Streams environment with one database that propagates changes, or you can configure an environment where changes are propagated between databases bidirectionally. Also, the tables for which data is shared do not need to be identical copies at all databases. Both the structure and the contents of these tables can differ at different databases, and the information in these tables can be shared between these databases.

See Also:

Data Warehouse Loading

Data warehouse loading is a special case of data replication. Some of the most critical tasks in creating and maintaining a data warehouse include refreshing existing data, and adding new data from the operational databases. Oracle Streams components can capture changes made to a production system and send those changes to a staging database or directly to a data warehouse or operational data store. Oracle Streams capture of redo data with a capture process avoids unnecessary overhead on the production systems. Support for data transformations and user-defined apply procedures enables the necessary flexibility to reformat data or update warehouse-specific data fields as data is loaded. In addition, Change Data Capture uses some of the components of Oracle Streams to identify data that has changed so that this data can be loaded into a data warehouse.

See Also:

Database Availability During Upgrade and Maintenance Operations

You can use the features of Oracle Streams to achieve little or no database down time during database upgrade and maintenance operations. Maintenance operations include migrating a database to a different platform, migrating a database to a different character set, modifying database schema objects to support upgrades to user-created applications, and applying an Oracle software patch.

Message Queuing

Oracle Streams Advanced Queuing (AQ) enables user applications to enqueue messages into a queue, propagate messages to subscribing queues, notify user applications that messages are ready for consumption, and dequeue messages at the destination. A queue can be configured to stage messages of a particular type only, or a queue can be configured as an ANYDATA queue. Messages of almost any type can be wrapped in an ANYDATA wrapper and staged in ANYDATA queues. Oracle Streams AQ supports all the standard features of message queuing systems, including multiconsumer queues, publish and subscribe, content-based routing, Internet propagation, transformations, and gateways to other messaging subsystems.

You can create a queue at a database, and applications can enqueue messages into the queue explicitly. Subscribing applications or messaging clients can dequeue messages directly from this queue. If an application is remote, then a queue can be created in a remote database that subscribes to messages published in the source queue. The destination application can dequeue messages from the remote queue. Alternatively, the destination application can dequeue messages directly from the source queue using a variety of standard protocols.

See Also:

Event Management and Notification

Business events are valuable communications between applications or organizations. An application can enqueue messages that represent events into a queue explicitly, or an Oracle Streams capture process or synchronous capture can capture database events and encapsulate them into messages called LCRs. These messages can be the results of DML or DDL changes. Propagations can propagate messages in a stream through multiple queues. Finally, a user application can dequeue messages explicitly, or an Oracle Streams apply process can dequeue messages implicitly. An apply process can reenqueue these messages explicitly into the same queue or a different queue if necessary.

You can configure queues to retain explicitly-enqueued messages after consumption for a specified period of time. This capability enables you to use Oracle Streams Advanced Queuing (AQ) as a business event management system. Oracle Streams AQ stores all messages in the database in a transactional manner, where they can be automatically audited and tracked. You can use this audit trail to extract intelligence about the business operations.

Oracle Streams capture processes, synchronous captures, propagations, apply processes, and messaging clients perform actions based on rules. You specify which events are captured, propagated, applied, and dequeued using rules, and a built-in rules engine evaluates events based on these rules. The ability to capture events and propagate them to relevant consumers based on rules means that you can use Oracle Streams for event notification. Messages representing events can be staged in a queue and dequeued explicitly by a messaging client or an application, and then actions can be taken based on these events, which can include an e-mail notification, or passing the message to a wireless gateway for transmission to a cell phone or pager.

Data Protection

One solution for data protection is to create a local or remote copy of a production database. In the event of human error or a catastrophe, the copy can be used to resume processing.

You can use Oracle Data Guard SQL Apply, a data protection feature that uses some of the same infrastructure as Oracle Streams, to create and maintain a logical standby database, which is a logically equivalent standby copy of a production database. As in the case of Oracle Streams replication, a capture process captures changes in the redo log and formats these changes into LCRs. These LCRs are applied at the standby databases. The standby databases are open for read/write and can include specialized indexes or other database objects. Therefore, these standby databases can be queried as updates are applied.

It is important to move the updates to the remote site as soon as possible with a logical standby database. Doing so ensures that, in the event of a failure, lost transactions are minimal. By directly and synchronously writing the redo logs at the remote database, you can achieve no data loss in the event of a disaster. At the standby system, the changes are captured and directly applied to the standby database with an apply process.

Sample Oracle Streams Configurations

Each of the following sections provide an overview of a sample Oracle Streams configuration:

Sample Hub-and-Spoke Replication Configuration

Figure 1-2 shows a sample hub-and-spoke replication configuration. A hub-and-spoke replication configuration typically is used to distribute information to multiple target databases and to consolidate information from multiple databases to a single database.

A hub-and-spoke replication configuration is one in which a central database, or hub, communicates with one or more secondary databases, or spokes. The spokes do not communicate directly with each other. In a hub-and-spoke replication configuration, the spokes might or might not allow changes to the replicated database objects.

In the sample hub-and-spoke replication configuration shown in Figure 1-2, there is one hub database and two spoke databases. The spoke databases allow changes to the replicated database objects.

Figure 1-2 Sample Hub-and-Spoke Replication Configuration

Description of Figure 1-2 follows
Description of "Figure 1-2 Sample Hub-and-Spoke Replication Configuration"

For more information about this configuration, see Oracle Database 2 Day + Data Replication and Integration Guide.

Sample Replication Configuration With Downstream Capture

Figure 1-3 shows a sample replication configuration that uses a downstream capture process. Downstream capture means that the capture process runs on a remote database instead of the source database. Using downstream capture removes the capture workload from the production database.

In the sample replication configuration shown in Figure 1-3, the downstream capture process runs at the remote database dest.example.com, and the redo data is sent from the source database src.example.com to the remote database. At the remote database, a downstream capture process captures the changes in the redo data sent from the source database and an apply process applies these changes to the local database objects.

Figure 1-3 Sample Replication Configuration With Downstream Capture

Description of Figure 1-3 follows
Description of "Figure 1-3 Sample Replication Configuration With Downstream Capture"

For more information about this configuration, see Oracle Database 2 Day + Data Replication and Integration Guide.

Sample Replication Configuration That Uses Synchronous Captures

Figure 1-4 shows a sample replication configuration that uses synchronous captures to capture changes instead of capture processes. You can use a synchronous capture replication configuration to replicate changes to tables with infrequent data changes in a highly active database or in situations where capturing changes from the redo logs is not possible.

Figure 1-4 Sample Replication Configuration With Synchronous Captures

Description of Figure 1-4 follows
Description of "Figure 1-4 Sample Replication Configuration With Synchronous Captures"

For more information about this configuration, see Oracle Database 2 Day + Data Replication and Integration Guide.

Sample N-Way Replication Configuration

Figure 1-5 shows a sample n-way replication configuration. An n-way replication configuration typically is used in an environment with several peer databases and each database must replicate data with each of the other databases. An n-way replication configuration can provide load balancing, and it can provide failover protection if a single database becomes unavailable.

An n-way replication configuration is one in which each database communicates directly with each other database in the environment. The changes made to replicated database objects at one database are captured and sent directly to each of the other databases in the environment, where they are applied.

In the sample n-way replication configuration shown in Figure 1-5, each of the three databases captures changes to the replicated database objects and sends these changes to the other two databases in the configuration. Apply processes at each database apply the changes sent from the other two databases.

Figure 1-5 Sample N-Way Replication Configuration

Description of Figure 1-5 follows
Description of "Figure 1-5 Sample N-Way Replication Configuration"

For more information about this configuration, see Oracle Streams Replication Administrator's Guide.

Sample Configuration That Performs Capture and Apply in a Single Database

Figure 1-6 shows a sample configuration that captures database changes with a capture process and applies these changes with an apply process in a single database. In this configuration, the apply process reenqueues the changes into the queue for processing by an application. Also, a DML handler inserts rows that were deleted from the hr.employees table into a hr.emp_del table.

Figure 1-6 Sample Single Database Capture and Apply Configuration

Description of Figure 1-6 follows
Description of "Figure 1-6 Sample Single Database Capture and Apply Configuration"

For more information about this configuration, see Chapter 32, "Single-Database Capture and Apply Example".

Sample Messaging Configuration

Figure 1-7 shows a sample messaging configuration. A messaging configuration sends messages from one queue to another queue. The two queues can be in the same database or in different databases. The messages can be dequeued and processed by applications in a customized way.

In the sample messaging configuration shown in Figure 1-7, a trigger at one database creates and enqueues messages. A propagation sends the messages to another database, where a PL/SQL procedure dequeues the messages and processes them.

Figure 1-7 Sample Messaging Configuration

Description of Figure 1-7 follows
Description of "Figure 1-7 Sample Messaging Configuration"

For more information about this configuration, see Oracle Database 2 Day + Data Replication and Integration Guide.

Administration Tools for an Oracle Streams Environment

Several tools are available for configuring, administering, and monitoring your Oracle Streams environment. Oracle-supplied PL/SQL packages are the primary configuration and management tools, and the Oracle Streams tool in Oracle Enterprise Manager provides some configuration, administration, and monitoring capabilities to help you manage your environment. Additionally, Oracle Streams data dictionary views keep you informed about your Oracle Streams environment.

Oracle-Supplied PL/SQL Packages

The following Oracle-supplied PL/SQL packages contain procedures and functions for configuring and managing an Oracle Streams environment.

DBMS_APPLY_ADM Package

The DBMS_APPLY_ADM package provides an administrative interface for starting, stopping, and configuring an apply process. This package includes procedures that enable you to configure apply handlers, set enqueue destinations for messages, and specify execution directives for messages. This package also provides administrative procedures that set the instantiation SCN for objects at a destination database. This package also includes subprograms for configuring conflict detection and resolution and for managing apply errors.

DBMS_CAPTURE_ADM Package

The DBMS_CAPTURE_ADM package provides an administrative interface for starting, stopping, and configuring a capture process. It also provides an administrative interface for configuring a synchronous capture. This package also provides administrative procedures that prepare database objects at the source database for instantiation at a destination database.

DBMS_COMPARISON Package

The DBMS_COMPARISON package provides interfaces to compare and converge database objects at different databases.

DBMS_PROPAGATION_ADM Package

The DBMS_PROPAGATION_ADM package provides an administrative interface for configuring propagation from a source queue to a destination queue.

DBMS_RULE Package

The DBMS_RULE package contains the EVALUATE procedure, which evaluates a rule set. The goal of this procedure is to produce the list of satisfied rules, based on the data. This package also contains subprograms that enable you to use iterators during rule evaluation. Instead of returning all rules that evaluate to TRUE or MAYBE for an evaluation, iterators can return one rule at a time.

DBMS_RULE_ADM Package

The DBMS_RULE_ADM package provides an administrative interface for creating and managing rules, rule sets, and rule evaluation contexts. This package also contains subprograms for managing privileges related to rules.

DBMS_STREAMS Package

The DBMS_STREAMS package provides interfaces to convert ANYDATA objects into LCR objects, to return information about Oracle Streams attributes and Oracle Streams clients, and to annotate redo entries generated by a session with a tag. This tag can affect the behavior of a capture process, a synchronous capture, a propagation, an apply process, or a messaging client whose rules include specifications for these tags in redo entries or LCRs.

DBMS_STREAMS_ADM Package

The DBMS_STREAMS_ADM package provides an administrative interface for adding and removing simple rules for capture processes, propagations, and apply processes at the table, schema, and database level. This package also enables you to add rules that control which messages a propagation propagates and which messages a messaging client dequeues. This package also contains procedures for creating queues and for managing Oracle Streams metadata, such as data dictionary information. This package also contains procedures that enable you to configure and maintain an Oracle Streams replication environment. This package is provided as an easy way to complete common tasks in an Oracle Streams environment. You can use other packages, such as the DBMS_CAPTURE_ADM, DBMS_PROPAGATION_ADM, DBMS_APPLY_ADM, DBMS_RULE_ADM, and DBMS_AQADM packages, to complete these same tasks, as well as tasks that require additional customization.

DBMS_STREAMS_ADVISOR_ADM Package

The DBMS_STREAMS_ADVISOR_ADM package provides an interface to gather information about an Oracle Streams environment and advise database administrators based on the information gathered. This package is part of the Oracle Streams Performance Advisor.

DBMS_STREAMS_AUTH Package

The DBMS_STREAMS_AUTH package provides interfaces for granting privileges to and revoking privileges from Oracle Streams administrators.

DBMS_STREAMS_MESSAGING Package

The DBMS_STREAMS_MESSAGING package provides interfaces to enqueue messages into and dequeue messages from an ANYDATA queue.

DBMS_STREAMS_TABLESPACE_ADM Package

The DBMS_STREAMS_TABLESPACE_ADM package provides administrative procedures for creating and managing a tablespace repository. This package also 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.

UTL_SPADV Package

The UTL_SPADV package provides subprograms to collect and analyze statistics for the Oracle Streams components in a distributed database environment. This package uses the Oracle Streams Performance Advisor to gather statistics.

See Also:

Oracle Database PL/SQL Packages and Types Reference for more information about these packages

Oracle Streams Data Dictionary Views

Every database in an Oracle Streams environment has Oracle Streams data dictionary views. These views maintain administrative information about local rules, objects, capture processes, propagations, apply processes, and messaging clients. You can use these views to monitor your Oracle Streams environment.

See Also:

Oracle Streams Tool in the Oracle Enterprise Manager Console

To help configure, administer, and monitor Oracle Streams environments, Oracle provides an Oracle Streams tool in the Oracle Enterprise Manager Console. You can also use the Oracle Streams tool to generate Oracle Streams configuration scripts, which you can then modify and run to configure your Oracle Streams environment. The Oracle Streams tool online Help contains the primary documentation for this tool.

Figure 1-8 shows the top portion of the Streams page in Enterprise Manager.

Figure 1-8 Streams page in Enterprise Manager

Description of Figure 1-8 follows
Description of "Figure 1-8 Streams page in Enterprise Manager"

Figure 1-9 shows the Oracle Streams Topology, which is on the bottom portion of the Streams page in the Enterprise Manager.

Figure 1-9 Oracle Streams Topology

Description of Figure 1-9 follows
Description of "Figure 1-9 Oracle Streams Topology"

See Also:

Oracle Streams Documentation Roadmap

Oracle Streams provides many options for setting up, managing, and monitoring information-sharing environments. This section provides a documentation roadmap to help you find the documentation you need.

The Oracle Streams documentation set includes the following documents:

This documentation roadmap is intended to guide you to the information you need in these documents.

This section contains the following topics:

Documentation for Learning About Oracle Streams

Before setting up an Oracle Streams environment, it is best to understand the features of Oracle Streams and how you can use them. Table 1-1 helps you find conceptual information about Oracle Streams.

Table 1-1 Documentation for Learning About Oracle Streams

For conceptual information about See

apply processes

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about applying database changes and other types of messages with apply processes

"Implicit Consumption with an Apply Process" for detailed information about apply processes

Oracle Streams Replication Administrator's Guide for information about apply processes that is specific to replication environments, such as information about applying changes with dependencies and applying DML and DDL changes

capture processes

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about capturing database changes that were recorded in the redo log using capture processes

"Implicit Capture with an Oracle Streams Capture Process" for detailed information about capture processes

Oracle Streams Replication Administrator's Guide for information about capture processes that is specific to replication environments, such as information about supplemental logging

capturing messages with applications (explicit capture)

"Explicit Capture by Applications" for an overview of capturing messages with applications

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about capturing messages with applications

Oracle Streams Advanced Queuing User's Guide for detailed information about capturing messages with applications

combined capture and apply optimization

"Combined Capture and Apply Optimization" for information about improving performance by sending database changes more efficiently from capture processes to apply processes in a replication environment

comparing and converging data

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about how to compare database objects at two different databases and about how to converge differences in these database objects

Oracle Streams Replication Administrator's Guide for detailed information about comparing database objects at two different databases and converging differences in these database objects

conflicts and conflict resolution

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about conflicts that result when changes are made to the same row in two or more replicated tables at nearly the same time, and for essential information about resolving these conflicts automatically

Oracle Streams Replication Administrator's Guide for detailed information about conflicts and conflict resolution

consuming messages with applications (explicit consumption)

"Explicit Consumption with Manual Dequeue" for an overview of consuming messages with applications

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about consuming messages with applications

Oracle Streams Advanced Queuing User's Guide for detailed information about consuming messages with applications

heterogeneous information sharing

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about working with non-Oracle databases

Oracle Streams Replication Administrator's Guide for detailed information about working with non-Oracle databases

high availability

Chapter 8, "Oracle Streams High Availability Environments"

Oracle Database High Availability Overview for information about your high availability options

information provisioning

Chapter 29, "Information Provisioning Concepts" for information about moving or copying large amounts of information efficiently

instantiation

"Instantiation in an Oracle Streams Environment" for essential information about preparing database objects for replication at two or more databases

Oracle Streams Replication Administrator's Guide for detailed information about instantiation

logical change records (LCRs)

"Logical Change Records (LCRs)" for information about how Oracle Streams uses messages that describe database changes

messaging clients

"Explicit Consumption with a Messaging Client"

Oracle Streams best practices

Oracle Streams Replication Administrator's Guide

Oracle Streams capabilities

"What Can Oracle Streams Do?"

Oracle Streams interoperability with other Oracle Database components

Appendix A, "How Oracle Streams Works With Other Database Components"

Oracle Streams restrictions

Appendix B, "Oracle Streams Restrictions"

Oracle Streams uses

"What Are the Uses of Oracle Streams?"

propagations

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about sending messages between queues

"Message Propagation Between Queues" for detailed information about propagations

queues

"Queues" for essential information about how queues store messages

Oracle Streams Advanced Queuing User's Guide for detailed information about queues

rules

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about rules and how Oracle Streams uses them

Chapter 5, "Rules" for general information about rules

Chapter 6, "How Rules Are Used in Oracle Streams" for information about the ways in which rules determine the behavior of Oracle Streams clients

rule-based transformations

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about how rule-based transformations support non-identical replicas of database objects

Chapter 7, "Rule-Based Transformations" for detailed information about rule-based transformations

synchronous captures

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about capturing database changes using synchronous captures

"Implicit Capture with Synchronous Capture" for detailed information about synchronous captures

tags

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about how tags can be used to add additional information to captured database changes

Oracle Streams Replication Administrator's Guide for detailed information about tags

user messages

"User Messages" for essential information about messages that are created and enqueued by users and applications

Oracle Streams Advanced Queuing User's Guide for detailed information about user messages


Documentation About Setting Up or Extending an Oracle Streams Environment

You can set up many different types of Oracle Streams environments, and you have several options for setting them up. Table 1-2 helps you find the documentation you need to set up an Oracle Streams environment.

Table 1-2 Documentation About Setting Up or Extending an Oracle Streams Environment

For instructions about See

setting up an Oracle Streams replication environment using a one-step procedure

Oracle Database 2 Day + Data Replication and Integration Guide for examples that use the one-step procedures in the DBMS_STREAMS_ADM package to set up the most common types of Oracle Streams replication environments

Oracle Streams Replication Administrator's Guide for detailed instructions about using the one-step procedures in the DBMS_STREAMS_ADM package, including information about decisions to make and tasks to complete before running a procedure

Oracle Database PL/SQL Packages and Types Reference for reference information about the one-step procedures in the DBMS_STREAMS_ADM package

setting up an Oracle Streams replication environment using Oracle Enterprise Manager

Online help for the Oracle Streams setup wizards in Oracle Enterprise Manager

Oracle Streams Replication Administrator's Guide for descriptions of the Oracle Streams setup wizards in Oracle Enterprise Manager and instructions for opening them

setting up an Oracle Streams replication environment by configuring components individually

Oracle Streams Replication Administrator's Guide for step-by-step instructions to set up an Oracle Streams replication environment by configuring individual components in the correct order

Oracle Database 2 Day + Data Replication and Integration Guide for an example that provides step-by-step instructions for setting up an Oracle Streams replication environment that uses synchronous captures

Oracle Streams Replication Administrator's Guide for the following examples:

  • An example that provides step-by-step instructions for setting up a simple replication environment that replicates changes to a single table

  • An example that provides step-by-step instructions for setting up a heterogeneous replication environment that includes a rule-based transformation

  • An example that provides step-by-step instructions for setting up an n-way replication environment with conflict resolution

Oracle Database PL/SQL Packages and Types Reference for reference information about the packages that can set up an Oracle Streams replication environment. These packages are described in "Oracle-Supplied PL/SQL Packages".

extending an Oracle Streams replication environment using a one-step procedure

Oracle Database 2 Day + Data Replication and Integration Guide for examples that use the one-step procedures in the DBMS_STREAMS_ADM package to extend the most common types of Oracle Streams replication environments by adding databases and tables

Oracle Database PL/SQL Packages and Types Reference for reference information about the one-step procedures that can extend an Oracle Streams replication environment

extending an Oracle Streams replication environment by configuring components individually

Oracle Streams Replication Administrator's Guide for step-by-step instructions to extend an Oracle Streams replication environment by configuring individual components in the correct order

Oracle Streams Replication Administrator's Guide for an example that provides step-by-step instructions for extending a heterogeneous replication environment

Oracle Database PL/SQL Packages and Types Reference for reference information about the packages that can extend an Oracle Streams replication environment. These packages are described in "Oracle-Supplied PL/SQL Packages".

setting up an Oracle Streams messaging environment

Oracle Database 2 Day + Data Replication and Integration Guide for the following examples:

  • An example that provides step-by-step instructions for setting up a messaging environment that sends messages between databases

  • An example that provides step-by-step instructions for setting up message notifications that inform applications when new messages are in a queue

Oracle Streams Advanced Queuing User's Guide for detailed instructions about setting up messaging environments

"Wrapping User Message Payloads in an ANYDATA Wrapper and Enqueuing Them"

"Dequeuing a Payload that Is Wrapped in an ANYDATA Payload"

"Configuring a Messaging Client and Message Notification" for an example that sets up e-mail notifications

Oracle Database PL/SQL Packages and Types Reference for reference information about the packages used to set up messaging environments, including DBMS_STREAMS_ADM, DBMS_STREAMS_MESSAGING, DBMS_AQADM, and DBMS_AQ

Oracle Streams best practices

Oracle Streams Replication Administrator's Guide for information about the best practices to follow when setting up an Oracle Streams environment

setting up a tablespace repository

"Using a Tablespace Repository"

setting up a file group repository

"Using a File Group Repository"


Documentation About Managing an Oracle Streams Environment

You can use Oracle-supplied PL/SQL packages and Oracle Enterprise Manager to manage an Oracle Streams environment. Table 1-3 helps you find the documentation you need to manage an Oracle Streams environment.

Table 1-3 Documentation About Managing an Oracle Streams Environment

For instructions about managing See

apply processes

Oracle Database 2 Day + Data Replication and Integration Guide for information about starting an apply process, stopping an apply process, and setting apply process parameters using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about managing apply handlers and apply tags using Oracle Enterprise Manager, and about dropping apply processes using Oracle Enterprise Manager

Chapter 16, "Managing Oracle Streams Information Consumption" for information about managing apply processes using Oracle-supplied packages

Oracle Streams Replication Administrator's Guide for information about managing apply processes in a replication environment using Oracle-supplied packages

capture processes

Oracle Database 2 Day + Data Replication and Integration Guide for information about starting a capture process, stopping a capture process, and setting capture process parameters using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about setting a first SCN or start SCN for a capture process using Oracle Enterprise Manager, and about dropping a capture process using Oracle Enterprise Manager

"Managing a Capture Process" for information about managing capture processes using Oracle-supplied packages

Oracle Streams Replication Administrator's Guide for information about managing supplemental logging

changing the DBID or global name of an Oracle Streams database

Oracle Streams Replication Administrator's Guide

comparing and converging data

Oracle Database 2 Day + Data Replication and Integration Guide for essential information about using the DBMS_COMPARISON package and its related data dictionary views

Oracle Streams Replication Administrator's Guide for detailed information about using the DBMS_COMPARISON package and its related data dictionary views

conflicts and conflict resolution

Oracle Streams Replication Administrator's Guide for information about avoiding conflicts and configuring conflict resolution

export/import and Oracle Streams

"Performing Full Database Export/Import in an Oracle Streams Environment"

information provisioning

Chapter 30, "Using Information Provisioning"

instantiation

Oracle Streams Replication Administrator's Guide for information about performing instantiations

logical change records (LCRs)

"Managing Extra Attributes in Captured LCRs"

Oracle Streams Replication Administrator's Guide

Oracle Streams best practices

Oracle Streams Replication Administrator's Guide for information about the best practices to follow when managing an Oracle Streams environment

Oracle-supplied packages related to Oracle Streams

Oracle Database PL/SQL Packages and Types Reference for reference information about the packages that you can use to manage an Oracle Streams environment. These packages are briefly described in "Oracle-Supplied PL/SQL Packages".

point-in-time recovery and Oracle Streams

Oracle Streams Replication Administrator's Guide

propagations

Oracle Database 2 Day + Data Replication and Integration Guide for information about enabling and disabling propagations using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about scheduling, unscheduling, and dropping propagations using Oracle Enterprise Manager

"Managing Oracle Streams Propagations and Propagation Jobs" for information about managing propagations using Oracle-supplied packages

Oracle Streams Advanced Queuing User's Guide for information about managing propagations using Oracle-supplied packages and other administrative interfaces

queues

Oracle Database 2 Day + Data Replication and Integration Guide for information about modifying queues and queue tables using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about managing queues, queue tables, and Advanced Queuing transformations using Oracle Enterprise Manager

Oracle Streams Advanced Queuing User's Guide for information about managing queues using Oracle-supplied packages and other administrative interfaces

"Managing Queues"

removing an Oracle Streams configuration

"Removing an Oracle Streams Configuration"

resynchronizing a source database

Oracle Streams Replication Administrator's Guide

rules

Oracle Enterprise Manager online help for information about managing rules using Oracle Enterprise Manager

Chapter 17, "Managing Rules" for information about managing rules using Oracle-supplied packages

rule-based transformations

Oracle Enterprise Manager online help for information about managing rule-based transformations using Oracle Enterprise Manager

Chapter 18, "Managing Rule-Based Transformations" for information about managing rule-based transformations using Oracle-supplied packages

synchronous captures

"Managing a Synchronous Capture" for information about managing synchronous captures using Oracle-supplied packages

tags

Oracle Streams Replication Administrator's Guide

troubleshooting

Oracle Database 2 Day + Data Replication and Integration Guide for information about responding to Oracle Streams alerts and managing apply errors using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about troubleshooting an Oracle Streams environment using Oracle Enterprise Manager

Chapter 20, "Troubleshooting an Oracle Streams Environment" for general information about troubleshooting an Oracle Streams environment

Oracle Streams Replication Administrator's Guide for information about troubleshooting an Oracle Streams replication environment

unavailable destination database

Oracle Streams Replication Administrator's Guide for information about splitting off an unavailable destination database from a replication environment and merging the database back into the replication environment when it becomes available again


Documentation About Monitoring an Oracle Streams Environment

You primarily use Oracle supplied PL/SQL packages, data dictionary views, and Oracle Enterprise Manager to manage an Oracle Streams environment. Table 1-4 helps you find the documentation you need to manage an Oracle Streams environment.

Table 1-4 Documentation About Monitoring an Oracle Streams Environment

For instructions about monitoring See

apply processes

Oracle Database 2 Day + Data Replication and Integration Guide for information about monitoring apply process properties and statistics using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about monitoring apply process parameters, apply handlers, and apply errors using Oracle Enterprise Manager

Chapter 25, "Monitoring Oracle Streams Apply Processes" for information about monitoring apply processes using data dictionary views

Oracle Streams Replication Administrator's Guide for information about monitoring apply processes in a replication environment using data dictionary views

capture processes

Oracle Database 2 Day + Data Replication and Integration Guide for information about monitoring capture process properties and statistics using Oracle Enterprise Manager

Oracle Enterprise Manager online help for information about monitoring capture process parameters using Oracle Enterprise Manager

"Monitoring a Capture Process" for information about monitoring capture processes using data dictionary views

Oracle Streams Replication Administrator's Guide for information about monitoring supplemental logging using data dictionary views

combined capture and apply optimization

"Determining Which Capture Processes Use Combined Capture and Apply"

"Determining Which Apply Processes Use Combined Capture and Apply"

compatibility

"Monitoring Compatibility in an Oracle Streams Environment" for information about listing database objects that are not compatible with Oracle Streams clients

conflicts and conflict resolution

Oracle Database 2 Day + Data Replication and Integration Guide for information about viewing update conflict handlers using data dictionary views

Oracle Streams Replication Administrator's Guide for information about monitoring conflict detection and update conflict handlers using data dictionary views

data dictionary views related to Oracle Streams

Chapter 21, "Oracle Streams Static Data Dictionary Views"

Oracle Database Reference

information provisioning

Chapter 31, "Monitoring File Group and Tablespace Repositories"

instantiation

Oracle Streams Replication Administrator's Guide

logical change records (LCRs)

Oracle Streams Replication Administrator's Guide for information about tracking LCRs through a stream

messaging

Oracle Database 2 Day + Data Replication and Integration Guide for information about viewing the messages in a queue, queue statistics, and queue subscribers using Oracle Enterprise Manager

Oracle Streams Advanced Queuing User's Guide for information about monitoring messaging environments using data dictionary views

"Monitoring Queues and Messaging"

"Monitoring Buffered Queues"

Oracle Streams administrators

"Monitoring Oracle Streams Administrators and Other Oracle Streams Users"

Oracle Streams pool

"Monitoring the Oracle Streams Pool"

Oracle Streams topology and performance statistics

Chapter 22, "Monitoring the Oracle Streams Topology and Performance"

propagations

Oracle Database 2 Day + Data Replication and Integration Guide for information about monitoring propagation properties and statistics using Oracle Enterprise Manager

"Monitoring Oracle Streams Propagations and Propagation Jobs" for information about monitoring propagations using data dictionary views

rules

Oracle Enterprise Manager online help for information about monitoring rules using Oracle Enterprise Manager

Chapter 26, "Monitoring Rules" for information about monitoring rules using data dictionary views

rule-based transformations

Chapter 27, "Monitoring Rule-Based Transformations" for information about monitoring rule-based transformations using data dictionary views

synchronous captures

"Monitoring a Synchronous Capture" for information about monitoring synchronous captures using data dictionary views

Note: Oracle Enterprise Manager currently does not support monitoring synchronous captures.

tags

Oracle Streams Replication Administrator's Guide for information about monitoring tags using data dictionary views


Documentation About Database Using Oracle Streams for Upgrade and Maintenance

You can use Oracle Streams to achieve little or no down time for one-time operations, such as upgrading a database. Table 1-5 helps you find the documentation you need to perform one-time operations with Oracle Streams.

Table 1-5 Documentation About Data Upgrade and Maintenance With Oracle Streams

For instructions about See

upgrading a database and using Oracle Streams to achieve little or no down time

Appendix D, "Online Database Upgrade with Oracle Streams" for information about using Oracle Streams to perform a database upgrade with little or no down time

performing database maintenance operations and using Oracle Streams to achieve little or no down time

Appendix E, "Online Database Maintenance with Oracle Streams" for information about using Oracle Streams to perform a database maintenance operations with little or no down time. These database maintenance operations include migrating a database to a different platform, migrating a database to a different character set, modifying database schema objects to support upgrades to user-created applications, and applying an Oracle Database software patch or patch set.