Here is what i do:
I have a Workbook of huge size.
I need to edit just a single sheet of that workbook and write the workbook back to disk.
Since reading the whole workbook takes quite some time, I am using:
to load just the sheet which I want to edit.
Now here is the problem.
If I load only the sheet i need and write back the workbook, the rest of the sheets data are gone.
And if I load the entire Workbook, it takes considerable amount of time which affects the performance.
This is correct and logical and expected behavior. When you read specific sheet(s) from the workbook other sheets would be discarded, so when you re-save the workbook only your specific sheet(s) is/are rendered.
If your workbook is large sized, we recommend you to optimize memory usage while working with large files with large datasets.
The other option is to use Light Cells API to improve performance and efficiency, as described in the next article.
If you still find any performance issue, let us know with sample code (runnable), template file, etc., we will check it soon.