I've got an analytic app in my company's Gallery. I have it set up to allow users to select a CSV or Excel file and then feed the column names into drop down lists to allow users to map column names to expected inputs.
This works fine in most cases. However, I today uploaded an Excel file with ~1MM rows. After completing upload, it asked whether I wanted the list of sheets, or Sheet1. I selected Sheet1, but none of the dropdowns populated with the field list.
If I select <list of sheets>, they all populate (of course, just with "Sheet Name").
This isn't an issue for smaller Excel or CSV files. Is there a limit on how many rows the Gallery can work with? And why would it have to look beyond the first row of the Excel spreadsheet anyway?