A recursive grep in ~/.mozilla/firefox showed that the only reference to the old unwanted file was in the binary file places.sqlite.
My places.sqlite was 11Mb. I look through the Prefs window showed that the default setting was to store history for minimum of 90 days. That seemed rather excessive, so I reduced it drastically. But that didn't reduce the size of the file any, nor did it banish the spurious URLbar suggestion when I typed /home/....
After some discussion with folks on IRC, it developed that Firefox may never actually reduce the size of the places.sqlite file at all. Even if it did reduce the amount of data in the file (which it's not clear it does), it never tells sqlite to compact the file to use less space. Apparently there was some work on that about a year ago, but it was slow and unreliable and they never got it working, and eventually gave up on it.
You can run an sqlite compaction by hand (make sure to exit your running firefox first!):
sqlite3 places.sqlite vacuum
But vacuuming really didn't help much. It reduced the size of the file from 11 to 8.8 Mb (after reducing the number of days firefox was supposed to store to less than a third of the original size) and it didn't get rid of that spurious suggestion.
So the only remaining option seemed to be to remove the file. It stores both history and bookmarks, so it's best to back up bookmarks before removing it. I backed up bookmarks to the .json format firefox likes to use for backups, and also exported them to a more human (and browser) readable bookmarks.html. Then I removed the places.sqlite file.
Success! The spurious recommendation was gone. Typing seems faster too (less of those freezes while the "awesomebar" searches through its list of recommendations).
So I guess firefox can't be trusted to clean up after itself, and users who care have to do that manually. It remains to be seen how much the file will grow now. I expect periodic vacuumings or removals will still be warranted if I don't want a huge file; but it's pretty easy to do, and firefox found the bookmarks backup and reloaded them without any extra work on my part.
In the meantime, I made a new bookmark -- hidden in my bookmarklets menu so it doesn't clutter the main bookmarks menu -- to the directory where I preview articles I'm writing. That ought to help a bit with future URLbar suggestions.
[ 11:00 Jan 11, 2009 More tech/web | permalink to this entry ]