• KOReader version: Up to 994
• Device: Independent

Issue

Bookmarks can increase the docsetting (metadata.*.lua) file rapidly, some of the files on my device are even as large as 500K, which means opening the file and then closing will write 500K. It's definitely less optimized, especially when the docsetting is not changed at all.

Steps to reproduce

At least we can have a 'is_changed" flag in docsetting.
A better choice is to separate the file into several chunks, and update only the changed ones.