Temporary files
Reports Builder creates temporary files during report execution:
- Swap files are created when you run a report that requires multiple passes
to format (for example, a report that has forward references such as a field
with Source of &Total Logical Pages). The swap file contains a first
pass copy of each page of the report that Reports Builder uses to determine
the length of the report and resolve any forward references. By the time
all of the pages have formatted, this file will be approximately twice
the size of the final ouput. While developing a report, you should exclude
forward referencing fields to cut down on testing time.
Swap files are named a unique identifier.
- Data cache files are used to cache all the data
records fetched from the database and the values of all summaries in the
report. The size of this file reflects the amount of data in the report.
Records are packed such that the space allocated for each column is just
enough to contain the current value, not the maximum size for each column.
Data Cache files are named datXXXX,
where XXXX is unique.
- Index files are used to track breaks in the report.
This file contains tree structures built to traverse the data according
to the relationships defined in the report's data model. The size of this
file depends upon:
- the number of groups in the report
- the number of records in each group
- the size of the break column(s) of each group
- the depth of the group tree
Index files are named idxXXXXX,
where XXXX is unique.
Temporary file size
Temporary files can grow very large for a number of reasons. To avoid
having large temporary files, consider the following:
- Perform calculations in queries, if possible.
This can reduce the size of the data caching file because the report does
not need to retrieve as much data as it would if the calculations were
performed in summary columns or formulas.
- Reduce the size and number of break columns per
break group, if possible. This can reduce the size of the index file because
it reduces the size of the tree structure in the file.
- Eliminate forward referencing (for example, fields with
Source of &Total Logical Pages),
if possible. This can eliminate the swap file because Reports Builder
does not have to save a copy of the report output in the swap file before
formatting.
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