DRAFT KB: Data Export Min Inflate Ratio

Symptoms

When performing an export using the Export Data Store Entity to Excel Smart Service and providing a "Document To Update" that is an existing Excel file, one the following errors might be encountered:

1. The decompressed version is 100x larger than compressed version. Unable to update file {0}. The file size of the 'Document to Update' is at least 100 times larger when uncompressed, which constitutes a security risk.
   
   
2. The decompressed version has a zip entry that is >4GB. Unable to update file {0}. The file size of the uncompressed 'Document to Update' is too large.

Cause

1. All Excel files exist as compressed .zip archives. During the export process, the given Excel file must be uncompressed before it can be read. As a part of this operation, the file is checked against a heuristic designed to detect Zip Bombs. An archive is considered a Zip Bomb if the uncompressed archive is at least 100 times larger than the compressed archive.
2. A .xlsx file when uncompressed from its .zip archive form will become substantially larger than it appears on the origin filesystem. To restrict the amount of memory that will be consumed during decompression, as soon as one of the child files within the zip archive is detected to be larger than 4GB, the process will be terminated. This can occur on large .xlsx documents (40MB and greater) that are have a very large amount of data, or do not have a high enough uncompressed/compressed size ratio such that #1 will occur, but still has enough redundant data, styles, or other metadata such that the file inflates to the 4GB threshold.

Action

1. Ensure that the Excel file is not a Zip Bomb. If you are experiencing the error, please inspect your Excel file for duplicated data, styles, or other metadata that may contribute to this issue.
2. To resolve this issue, inspect your Excel file for duplicated data, styles, or other metadata that may contribute to this issue. If a file has all formatting removed and the error persists, then the file is too large to be updated.