Set the folder property Visible to user for each of these complex folders to No for
14-2 Oracle Fusion Middleware Administrators Guide for Oracle Business Intelligence Discoverer
What are summary folders?
Summary folders are a representation of queried data created in Discoverer Administrator that has been saved for reuse. The data is stored in the database in one
of the following depending on the edition of Oracle:
■
materialized views Discoverer uses materialized views to store summarized data in Oracle Enterprise
Edition databases.
■
tables Discoverer uses tables to store summarized data in Oracle Standard Edition
databases. The tables created by Discoverer to store summarized data are called Discoverer
summary tables. For more information about Discoverer summary tables, see What are Discoverer summary tables?
. Summary folders improve the response time of a query because the query accesses
pre-aggregated and pre-joined data rather than querying against the detail database tables.
You can also direct Discoverer to use summary folders based on tables containing summary data that have been created by another application. These tables are known
as external summary tables. You can specify that Discoverer refreshes external summary tables.
You can create summary folders in one of two ways:
■
using the Automated Summary Management ASM feature for more information, see
What is Automated Summary Management ASM
■
manually for more information, see What is manual summary folder creation?
The recommended method for creating summary folders in Discoverer is to use Automated Summary Management ASM.
What are Discoverer summary tables?
Discoverer summary tables are database tables created by Discoverer Administrator that contain summarized data. Discoverer summary tables contain pre-aggregated and
pre-joined data, and can improve query performance in Discoverer Plus and Discoverer Viewer.
Discoverer automatically recognizes when a summary table is available and rewrites the query to use the summary table. For more information, see
What is query rewrite?
. For example, when a query is run for the first time in Discoverer Plus it retrieves data
from the detail tables. This may require a multiple table join and aggregation over thousands or millions of rows, which could take some time to complete. If Discoverer
has created a suitable summary table, the same query retrieves data from the summary table and will return results in a few seconds. Both queries will produce the
same results.
For more information about Discoverer and rewriting queries to summary tables with Oracle Standard Edition databases, see
Example illustrating the advantages of rewriting a query to use a summary table
.
Note: Circumstances sometimes prohibit the creation of materialized views and result
in the creation of Discoverer summary tables when running against Oracle databases
Managing Summary Folders 14-3
Enterprise Edition release 9.2.0.7 or later. For more information, see What is
different between mapping external summary tables and views to EUL items, with Oracle Enterprise Edition databases?
.
What are materialized views?
Materialized views are database objects that contain the results of a query created by an Oracle Enterprise Edition database. The query results contain pre-aggregated and
pre-joined data and can improve query performance in Discoverer Plus and Discoverer Viewer.
Oracle Enterprise Edition databases automatically recognize when a materialized view can be used to satisfy a query request. The database rewrites the query to use the
materialized view. Queries are then directed to the materialized view and not to the underlying detail tables or views.
Materialized views have the following characteristics:
■
Materialized views consume storage space. Unlike ordinary views, materialized views contain data resulting from a query
against one or more detail tables.
■
Materialized views must be refreshed when data changes. The Oracle database maintains data in materialized views by refreshing the
materialized views after changes are made to the detail tables. You can configure Discoverer:
■
to set the Refresh Type to incremental that is, fast refresh, where only the changes made to the detail tables are refreshed or full that is, complete,
where the database executes the defining subquery of the materialized view
■
to set the Refresh to On demand manually maintained by the Discoverer manager or On commit whenever a database transaction commits its
changes to the detail tables, where the materialized view is in the same database as the detail tables
■
Materialized views are transparent to Discoverer users. Query rewrite transforms a SQL statement expressed in terms of the detail table
into a statement accessing one or more materialized views that are defined on the detail tables. For more information, see
What is query rewrite? .
Notes
■
You do not need to register external materialized views with Discoverer for end user queries to use them, as the database knows whether a materialized view can
satisfy the query. You only register an external materialized view with Discoverer if you want Discoverer to maintain the refresh for you for more information about
registering external summary tablesviews, see
How to create summary folders based on external summary tables
.
■
The SQL InspectorExplain Plan in Discoverer Plus indicates whether the SQL generated to run a query used a summary table or a materialized view for more
information, see About viewing the SQL and execution plan for query rewrite in
Discoverer .
■
For an historical context about Discoverer’s use of summary tablesmaterialized views, see
What is the context and future for Discoverer’s use of summary tablesmaterialized views?
.
14-4 Oracle Fusion Middleware Administrators Guide for Oracle Business Intelligence Discoverer
For more information about the differences between Discoverer summary tables and materialized views, see:
■
What characteristics differ between summary folders in Oracle Standard Edition databases and Oracle Enterprise Edition databases?
■
What is different about summary folders that are based on external summary tables?
■
What is different between mapping external summary tables and views to EUL items, with Oracle Enterprise Edition databases?
What is Automated Summary Management ASM
Automated Summary Management ASM is a Discoverer facility that creates and manages summary folders for you.
ASM simplifies the process of summary folder creation and maintenance by offering you a fully automated solution to summary folder management. When run
periodically, ASM can automatically refine the summary folders it creates using query statistics gathered by Discoverer from user queries. ASM also provides guidance if
you want to control the specification of default values during summary folder creationmaintenance.
How does ASM work?
ASM determines how to create summary folders by:
■
analyzing your database tables
■
using query statistics when available
■
using default values known as the ASM policy for more information, see What is
the ASM policy? ASM automatically creates and maintains the best set of summary folders based on the
above combination. ASM converts your summary policy into a list of recommended summary folder
definitions. You can either implement these recommendations without further intervention the actual set of summary tables dynamically adjusts with system usage
or execution can be stalled until you have specifically sanctioned one or more of the recommendations.
ASM requires table space to create summary folders but you can adjust how much space in the Summary Wizard for more information, see
How to run ASM using the Summary Wizard
.
Note: ASM works on the EUL as a whole, not just the currently selected business
areas. So ASM can use folders from all business areas in the current EUL.
What are the prerequisites for creating summary folders with ASM?
To create summary folders with ASM, the following requirements must be met:
■
The database must support PLSQL.
■
The DBMS_JOB package must be installed for scheduling summary folder creation and refresh for more information, see
How to confirm that DBMS_JOB is installed for summary management
.
Managing Summary Folders 14-5
■
The User ID that you intend to use to create the summary folders must have the following database privileges for more information, see
How to use SQLPlus to grant the privileges required to create summary folders
:
■
CREATE TABLE
■
CREATE VIEW
■
CREATE PROCEDURE
■
SELECT ON V_PARAMETER
■
CREATEDROPALTER ANY MATERIALIZED VIEW Oracle Enterprise Edition databases
■
GLOBAL QUERY REWRITE Oracle Enterprise Edition databases
■
ANALYZE ANY
■
The User ID that you intend to use to create summary folders must have sufficient quota in the tablespace for the summary tables to be created for more
information, see How to determine and reset tablespace quotas
.
■
You must connect to Discoverer Administrator as the EUL owner.
■
If you are using an Oracle Enterprise Edition database, your folders must not contain SET operators for example, UNION, UNION ALL, MINUS, INTERSECT.
If ASM finds a folder that contains a SET operator, summary data will not be created for that folder.
Note: For more information about Oracle SET operators, see the Oracle Database SQL
Reference Guide. Note:
A database user created in Discoverer may need additional privileges to enable them to create summary folders. The conditions that determine when this is true are
detailed in the following table, that illustrates when a database user created in Discoverer requires additional privileges to create summary folders:
What are the different ways to run ASM and when do you use them?
The following table shows the different ways that you can run ASM and when to use them:
Version of Discoverer and database version
under which the database user was created
Does database user require further privileges to create
summary folders?
What action is required?
Discoverer 3.1. Yes, the database user requires
further privileges to create summary folders.
You must explicitly grant the required privileges to the
database user for more information about how to
grant these privileges, see
How to use SQLPlus to grant the privileges required to
create summary folders .
Discoverer 4i against an Oracle Standard Edition
database. Yes, the database user requires
further privileges to create summary folders.
Same action as above. Discoverer 4i against an
Oracle Enterprise Edition database.
No, the database user requires no further privileges to create
summary folders. No action is required.
14-6 Oracle Fusion Middleware Administrators Guide for Oracle Business Intelligence Discoverer
What is the ASM policy?
The ASM policy is a set of user defined constraints and options that enable you to control how ASM behaves and what summary folders it produces.
The ASM policy is divided into space options and advanced settings. In many cases you will only need to set the space options.
For more information about space options and advanced settings, see:
■
Summary Wizard ASM: Step 3 Allocate Space dialog
■
Summary Wizard ASM: List of dialogs Discoverer provides default settings that ensure suitable summary folders are created
and maintained without your intervention. The minimum information required for an ASM policy is a tablespace name and an
allocated amount of disc space. The tablespace defaults to the user tablespace, and a default amount of disc space is used. Both of these values can be changed if required
for more information, see Summary Wizard ASM: Step 3 Allocate Space dialog
.
Why must you refresh summary data?
You must refresh summary data regularly to keep summary tables and materialized views consistent with the database. If the database changes often, summary tables and
materialized views need to be refreshed accordingly to keep their data current with the underlying database.
For information about refreshing summary folders see:
■
What happens when a summary folder is refreshed?
■
How to manually refresh a summary folder
■
About refresh options for Oracle Enterprise Edition databases
■
About refreshing summary folders following import between Oracle databases
Note: Sometimes it is useful to refresh a summary folder after a change has occurred
for example, the loading of data into a data warehouse. You can use the Discoverer command-line interface facility to automatically refresh a summary folder for more
information, see Chapter 22, Discoverer Command-line Interface
.
How to run ASM? Why run ASM this way?
For information see Using the Summary
Wizard. Discoverer leads you through
the whole process. How to run ASM using the
Summary Wizard .
Using the Load Wizard after bulk load.
Enables you to create summary folders during the load of a
business area without having to access ASM independently.
How to run ASM after bulk load using the Load Wizard
.
Using the command-line interface.
Enables you to create summary folders without having to start
Discoverer. How to run ASM using the
command-line interface .
Using a batch file and the Operating System
scheduler. Automates the scheduling of
ASM summary folder creation through the command line.
How to run ASM using a batch file and the operating
system scheduler .
Managing Summary Folders 14-7
What happens when a summary folder is refreshed?
When a summary folder is refreshed when running against Oracle Enterprise Edition databases, the database server’s own refresh mechanism is used this can be an
incremental refresh depending on your refresh settings.
Whenever a summary folder is refreshed, the following actions are performed by Discoverer:
■
The summary folder is marked as unavailable.
■
The materialized view or summary table associated with summary folder is reconciled against its EUL metadata and if necessary the definition is updated.
■
All existing summary data that is about to be refreshed is deleted.
■
The summary data is regenerated and inserted into the corresponding materialized views or summary tables.
■
The summary folder is marked as available.
How to run ASM using the Summary Wizard
You need certain database privileges to run ASM for more information about the privileges required to run ASM, see
What are the prerequisites for creating summary folders with ASM?
. To see a list of headings that point to more information about the Summary Wizard
dialogs, see Summary Wizard ASM: List of dialogs
. To start the summary wizard: