About two year ago we wrote about how to improve the start-up performance of Firefox 3.5 (yes, that is correct Firefox 3.5). One of the tips was the use of the add-on Vacuum Places Improved. Firefox 4.0 introduced automated and better management of the Places (history and bookmarks) database. I had forgotten all about this add-on until the other day when I was going through the Wiki updating the extensions and tweaks sections for compatibility with the newer versions of Firefox. I didn’t really think much of it then, but had noticed the add-on developer did bump the extension to work with Firefox 4.0 and newer. I still had a lot of work to do on the Wiki and I ended up forgetting about this add-on.

Over the weekend on Go Firefox! was a post from a user who finally made the jump from Firefox 3.6.x to 4.0.x (just in time for Firefox 5 to come out this week). They asked about the Vacuum Places Improved extension if it was needed. Checking around on my multiple profiles I noticed that I did not have this add-on installed on almost all of them. There was on older testing profile that I had ported over to one the newer developmental versions of Firefox which still had this add-on installed.

Well I decided I should ask around about this as I was kind of curios if this was really necessary anymore. Part of my uncertainty was that the extension had been bumped up to support Firefox 6.0. So I asked over at Firefox Builds. A couple people replied to my post and confirmed that indeed, Firefox 4 “will vacuum the database, and it will allocate new space in chunks.” However, they also cautioned that continuous vacuuming could actually do more harm than good. Especially doing a vacuuming once a day or even monthly.

Bug 512854 dates back to August 2009 which was about the time Firefox 3.7 (what would eventually become Firefox 4.0) was just starting to be developed, which discusses the integration into possibly Gecko 1.9.2 (Firefox 3.6 which at time was on the Alpha 1 release) including under what circumstances and when the vacuuming should take place.

Bottom line, there is really no need to have this extension. It might be helpful to use it as a ‘one-time cleanup’ if you have a really old profile or very heavy usage of Firefox. Ironically, it will help the performance of Firefox, especially on start up a little bit by not having this extension installed (or any others that you are not using).