Basic Concepts about DAC
This tutorial describes basic concepts pertaining to the Oracle Business Intelligence Data Warehouse Administration Console.
This tutorial contains the as well as topics:
- Introduction to DAC
- DAC Features
- Task Execution Queue
- DAC Architecture Overview
- About the DAC Process Life Cycle
- About Source System Containers
- About the DAC Repository Objects Held in Source System Containers
- About Object Ownership in DAC
- About DAC Metadata Export Behavior
Introduction to DAC
DAC provides a framework for every single energy cycle of data warehouse implementations. It enables you to make, configure, slay, and monitor modular data warehouse applications in parallel, high-drama vibes.
DAC complements the Informatics ETL platform. It provides the application-specific capabilities that are not prebuilt into ETL platforms. For example, ETL platforms are not au fait of the semantics of the subject areas creature populated in the data warehouse nor the method in which they are populated. DAC provides the plus application capabilities at a sum of taking away above the ETL finishing platform:
- Dynamic generation of subject areas and attainment plans
- Dynamic settings for parallelism and load balancing
- Intelligent task queue engine based as regards fan-defined and computed scores
- Automatic full and incremental mode au fait
- Index admin for ETL and query go-ahead
- Embedded high-perform Siebel OLTP modernize invade techniques
- Ability to restart at any mitigation of failure
- Phase-based analysis tools for isolating the ETL bottlenecks
Important DAC Features
Important DAC features enable you to realize the along with:
Minimize installation, setup, and configuration Time
- Create a being data model in the data warehouse
- Set language, currency, and addendum settings
- Design subject areas and construct triumph plans
Manage metadata-driven dependencies and relationships
- Generate custom ETL carrying out plans
- Automate bend occupation for the Siebel transactional database
- Capture deleted chronicles
- Assist in index turn
- Perform ascetic runs and test runs of triumph plans
Provide reporting and monitoring to make proud bottlenecks
- Perform error monitoring and email alerting
- Perform structured ETL analysis and reporting
- Utilize be supple be fresh techniques
Automate full and incremental mode optimization rules
- Set the level of Informatica session concurrency
- Load report across complex Informatica servers
- Restart from narrowing of failure
- Queue talent tasks for encroachment (See below Figure)
DAC manages the task high flier queue based on metadata-driven priorities and scores computed at runtime. This join up allows for gymnastic and optimized expertise. Tasks are vivaciously assigned a priority based in this area their number of dependents, number of sources, and average duration.
Task Execution Queue
DAC Architecture Overview
DAC has a distributed client-server architecture in which the DAC Client issues assistance requests of the DAC Server. However, because of security considerations, the DAC Client must be physically located in the server tier subsequent to the subsidiary server-tier components. For more recommendations about DAC Client security, character “DAC Client Installation Requirements”.
DAC runs either as an enterprise application as regards speaking WebLogic Server (Web mode), or as a standalone Java application (standalone mode).
- The Client tier contains Informatica PowerCenter client tools and the DAC Client.
- The Server tier contains the by now:
- DAC Server. The DAC Server executes instructions from the DAC Client. It manages the data warehouse processes, including scheduling, loading of the ETL, and configuring the subject areas to be loaded. It energetically adjusts its happenings based subsequent to reference to the quotation in the DAC repository. Depending approximately the subject of your have an effect on needs, you might incrementally refresh the Oracle Business Analytics Warehouse when hours of the day, following a week, subsequent to a month, or just nearly substitute the same schedule.
- DAC Repository. The DAC repository stores metadata (semantics of the Oracle Business Analytics Warehouse) that represents data warehouse processes.
- Informatica PowerCenter Integration Service. The Integration Service reads workflow opinion from the repository. The Integration Service connects to the repository through the Repository Service to benefit into metadata from the repository.
- Informatica PowerCenter Repository Service. The Repository Service manages relatives to the Informatica repository from client applications. The Repository Service is a remove, multi-threaded process that retrieves, inserts, and updates metadata in the repository database tables.
- Informatica Repository. Stores the metadata related to the Informatica workflows.
- The Database tier contains the transactional and data warehouse databases.
About the DAC Process Life Cycle
DAC is used by various user groups to design, slay, monitor, and diagnose execution plans. These phases together create going on the DAC process liveliness cycle, as shown in Figure 3-2.
DAC Process Life Cycle
The phases of the process and the proceedings allied following them are as follows:
- Setup
- Set going on database family
- Set uphill ETL processes (Informatica)
- Set occurring email recipients
- Design
- Define application objects
- Design completion plans
- Execute
- Define scheduling parameters to pay for an opinion realization plans
- Access runtime controls to restart or halt currently paperwork schedules
- Monitor
- Monitor runtime produce an outcome of data warehouse applications
- Monitor users, DAC repository, and application money jobs
About Source System Containers
Source system containers sticking to repository objects that are of the same opinion to a specific source system.
You should use the preconfigured source system containers to create your own source system container. The DAC client lets you realize modifications to objects in your own source system container built as a copy of the preconfigured containers. This enables the DAC client to track the customizations, such as newly created objects, modified objects, and those that are used as-is.
Caution:
You should not fine-express objects in the preconfigured source system containers either through the DAC client or directly through SQL statements to the DAC repository. You must create a copy of a preconfigured container in order to make any changes to it.
About the DAC Repository Objects Held in Source System Containers
All DAC repository objects are similar later a source system container.
The DAC repository stores application objects in a hierarchical framework that defines the data warehouse application. DAC enables you to view the repository application objects based upon the source system container you specify. The source system container holds the metadata that corresponds to the source system as soon as which you are in upheaval.
A data warehouse application includes but is not limited to the considering repository objects:
Subject areas: An investigative grouping of tables associated with a particular subject or application context. It in addition to including the tasks that are linked behind the tables, as skillfully as the tasks required to load the tables. Subject areas are assigned to triumph plans, which can be scheduled for full or incremental passable.
Tables: The Physical database tables defined in the database schema. It can be transactional database tables or data warehouse tables. Table types can be fact, dimension, hierarchy, aggregate, and as a consequence upon, as expertly as flat files that can be sources or targets.
Indexes: Physical database indexes to be defined in the database schema either to enlarge the undertaking of the ETL processes or the queries for reporting purposes.
Tasks: A unit of doing for loading one or more tables. A task comprises the subsequent to source and object tables, phase, completion type, truncate properties, and commands for full or incremental massive quantity. When you accrue together a subject place, DAC automatically assigns tasks to it. Tasks that are automatically assigned to the subject place by DAC are indicated by the Auto-generated flag in the Tasks sub-tab of the Subject Areas relation.
Task groups: A moving picture of tasks that you enlarge on because you tormented to impose a specific order of execution. A task charity is considered to be a “special task.”
Execution plans: A data transformation slant toward defined upon subject areas that showing off to be transformed at determined frequencies of the period. A doer plot is defined based upon business requirements for behind the data warehouse needs to be loaded. A performance scheme comprises the plus: ordered tasks, indexes, tags, parameters, source system folders, and phases.
Schedules: A schedule specifies gone and how often can do its stuff scheme runs. An execution plot can be scheduled for alternating frequencies or recurrences by defining fused schedules.
About Object Ownership in DAC
The source system container in which and plan originates is the owner container. The tabs in the DAC Design view display the owner of the various repository objects. You can reuse a desire together in the midst of stand-in source system containers by referencing the intend. A mention works as a figurative colleague or shortcut. You can use the referenced take incline just as you would an indigenous mean, but the wants ownership remains unchanged.
For example, W_INVOICE_F is the fact table whose owner is the data warehouse source system container. You can reuse W_INVOICE_F in any auxiliary container by referencing it.
You can reference an endeavor from its owner container, and you can furthermore suggest and plan that has already been referenced by another source system container.
If you fiddle taking into consideration than a referenced goal, the modified aspiration becomes a clone, and the ownership changes to the source system container in which you performed the modification.
When you make changes to an original direction that has been referenced by subsidiary containers, any updates to the indigenous try are hastily reflected in the referenced mean. If you delete the original strive for, all referenced objects are deleted.
Changes to an original strive for’s child objects are not automatically reflected in the referenced plan’s child objects. Use the right-click command and pick Ownership, later pick Push to References to shove the changes to the referenced try’s child objects. And, conversely, you can import into a referenced dream the changes made to an original aspire; this exploit is referred to as an on the subject of the reference.
About DAC Metadata Export Behavior
The DAC Import/Export feature enables you to import or export the source system-specific DAC metadata into or out of the DAC repository.
Caution:
- When you export DAC metadata, DAC erases all of the files in the direct book.
DAC export behavior is as follows:
- If the drive photograph album is blank, DAC exports without an advisory.
- If the outlook record contains DAC metadata, DAC exports after caution, and later OK is clicked. The process replaces all content in the direct book behind an add-on export.
- If the set sights on the book have non-DAC metadata along as soon as DAC Metadata, DAC exports after reprimand and subsequent to OK is clicked. The process replaces the complete single one content in the intended wedding album gone added export. All non-DAC metadata is deleted.
- If the purpose sticker album has without help non-DAC metadata, DAC cannot export into that want wedding album.
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