When a file is uploaded, Confluence will attempt to extract and index its text.
This process is quite memory intensive and can cause out of memory errors when very large files are uploaded.
Confluence has a number of safeguards to prevent this happening:
If the uploaded file is larger than 100 MB:
If the uploaded file is one of the following types, Confluence will only extract up to:
1 MB of text from Excel (.xlsx) and PowerPoint (.pptx)
8 MB of text from PDF (.pdf)
10 MB of text from other text files (including .txt, .xml, .html, .rtf etc)
16 MB of text from Word (.docx)