hello manutmu, the database size where bookmarks are stored will be increased but i think the effects on performance will be quite negligible. i think the impact of an extensive browser history will be bigger & normally the process of clearing up some old history entries will kick in once a few ten thousand pages are reached...

Note that SQLite database files like places.sqlite have fixed minimum size of 10 MB and its size gets incremented in 10 MB chunks, so you won't notice a change in size.

A large history is more likely to show performance effects than more bookmarks as you can easily have over 50,000 history items, but having that much bookmarks is less likely.
The visited link count may need to adjusted if you visit an URL that you have bookmarked or have visited before.