Publishing Reports to the Web - Downloads - Oracle

Methodology
See the Oracle9iAS Best Practices in Performance and Scalability: Application Design and
Configuration white paper on OTN, (http://otn.oracle.com), for more
performance tips on JSP technology.
20.1.4 General Layout Guidelines
This section outlines the various guidelines that you can follow when designing your
report’s layout.
20.1.4.1 Fetching Ahead
Oracle Reports enables you to display data such as total number of pages or grand
totals, in the report margins or on the report header pages. This option, although
useful, forces the entire report to be “fetched ahead". Fetching-ahead requires the
entire report to be processed before the first page can be output. The usual model is to
format pages as and when required.
Although the fetched-ahead functionality does not affect the overall time the report
takes to generate, it affects the amount of temporary storage required and the time
taken before the first page can be viewed. This is an example of perceived performance as
opposed to actual performance. If the report is to be output to the screen in a
production environment, fetching ahead should be avoided unless the performance
variance is deemed acceptable.
20.1.4.2 Bursting and Distribution
With the introduction of report bursting, a report layout can be made up of three
distinct sections: header, body, and trailer. A report can comprise all three sections, or
it can be viewed as three separate reports within one report. Oracle Reports allows you
to control bursting at group record level offering a further level of granularity. This is
made possible by the Distribution and Repeat On properties for each individual
section. The performance gain is evident when bursting is used in conjunction with
distribution, allowing each section of a report to have multiple formats and sent to
multiple destinations. Once the distribution options has been set the report needs only
to be run once, to be output to multiple destinations with a single execution of the
query(s). Previously the report had to be executed multiple times.
When you implement bursting and distribution in a report, you can generate
section-level distribution by setting the Repeat On property for a section to a data
model break group, which generates an instance of the section for each column record
of that break group. Then, you can distribute each instance of the section as
appropriate (for example, to individual managers in the MANAGER group).
If you set the Repeat On property for more than one of the Header, Main, and Trailer
sections of a report, all Repeat On property values must be set to the same data model
break group. If the Repeat On property for any one of the Header, Main, and Trailer
sections is set to a different data model break group, Oracle Reports raises any of the
following messages:
REP-0069: Internal Error
REP-57054: In-Process job terminated: Terminated with error
REP-594: No report output generated
20.1.5 Calling Oracle Reports from Forms
Applications built using Forms Builder and Reports Builder require reports on data
that has already been retrieved/updated by the Oracle Application Server Forms
Services section of the application. The tight product integration between Oracle
Tuning Oracle Reports 20-15