Firefox 3 sluggish?

Reported in many other places, but may be of interest also here.

If your Firefox 3 installation is becoming sluggish and/or unresponsive, especially when typing in the address bar or using other autocompletion features, make sure you’ve the sqlite3 binary installed, and try:

find ~/.mozilla/firefox -name "*.sqlite" -exec sqlite3 -line '{}' 'vacuum;' \;

Worked like a charm here.