Once cleared, the history can not be recovered.

So your saying that once you hit the clear all history button, search history is gone for ever? As compared to internet explorer where it could still be recovered?

MS has a habit to store all kinds of data in the registry. You'd be surprised what would show up if you would search for it. The NTFS file system makes it easier than ever to recover deleted files by only setting a delete flag flag and not removing any file name or index and cluster data that FAT 16 and FAT 32 do. Firefox stores the history in a SQLite database file, so if you delete the history then you clear those records in the file that usually can't be recovered. There is an Undo history kept for the bookmarks (Ctrl + Z in the Library) that you use to restore deleted bookmarks if you delete any by accident and haven't closed Firefox.