HP Intelligent Management Center Standard Software Platform - Manual (Page 165)

Evaluation times for date functions in
BusinessObjects Enterprise
Different date and time functions available in Crystal Reports are evaluated
at different stages during report processing. Some are evaluated when a
scheduled report is processed, or when a report instance is refreshed: this
evaluation time is known as "WhileReadingRecords." Others are evaluated
each time a report page is formatted for display in a report viewer or a
browser: this evaluation time is known as "WhilePrintingRecords."
If you use BusinessObjects Enterprise to generate report instances and
notice that date or time functions are not evaluating to the values that you
expect, consider the following:
• The current date and time are always read from the clock that is locally
accessible to the Report Engine—that is, from the clock on the computer
that processes the report. In BusinessObjects Enterprise, the Job Server
processes scheduled reports against the database, and the Page Server
processes on-demand reports against the database. The Page Server
also formats individual pages of report instances when users view them.
• When a scheduled report is processed, all date and time formulas are
evaluated by the Job Server in order to generate the report instance.
When you simply view the resultant report instance, none of the formulas
is re-evaluated.
• When you view a cached report page, none of the date functions is
re-evaluated, because the records have already been read and the page
has already been formatted.
• If you use date and/or time functions in a report's selection formula, the
report's data is dependent upon the return values of those formulas.
Consequently, when you view a report instance at a later date, the function
may cause the report data to be updated from the database.
• To ensure that date and time functions return the values that you expect,
you can force the evaluation time through the use of the
WhileReadingRecords and WhilePrintingRecords functions.
For more information, see the "Functions" and "Report Processing Model"
sections of the Crystal Reports Online Help.
Crystal Reports 2008 SP3 User's Guide 165
8 Designing Optimized Web Reports
Scale with BusinessObjects Enterprise