323658 - Disable prefetching by default

Status: RESOLVED WONTFIX

(Firefox :: General, defect)

Description

[u88484]

I believe that prefetching is a big problem with the users complaining of "memory leaks". A bunch of users who have complained of memory leaks and I have suggested disabling prefetching have said that it helped a lot. I think prefetching maybe running rabid and prefetching links on pages that were prefetched and so on...might be the root of the users complaining that firefox memory useage grows as firefox sits unused in the background!?

Should be just changing this to false

http://lxr.mozilla.org/mozilla/source/modules/libpref/src/init/all.js#644

Would submit a patch but somehow messed up my cvs installtion

Comment 1

[Shayne Jewers]

Attachment: Flip the pref to false

Comment 2

[Mike Connor [:mconnor]]

Unless you have some proof that prefetching is the cause, there is absolutely no reason to disable something that is a valuable feature.  If something in the prefetching code is leaking memory, we should fix that, not disable a useful feature (and push site admins back to the unblockable hidden iframe solution).

Comment 3

[u88484]

I'm just asking to disable by default not remove this feature. Maybe I'm missing something but you said it's a valuable feature, what makes it valuable? Do most people even need prefetching now-a-days? Most connections are fast enough that prefetching and not prefetching makes no difference. Only thing I see this doing is loading all kinds of unwanted things into cache causing joe end user to complain about memory issues and they can't explain why they can watch the memory grow considerably whilst not surfing (most likely being prefetching doing its job) but explain that to him.

I suggested for people having memory issues to disable this and they reported back it helped out a lot. 

What do you mean by:
"and push site admins back to the unblockable hidden iframe solution" ?

Most admins don't like prefetching because it uses up there valuable bandwidth for most of the time no reason because who is to say the user is going to go to that page that was prefetched or not? Why take the chance of wasting the bandwidth?

Comment 4

[Mike Connor [:mconnor]]

Site admins have options to block prefetch traffic on the server level, if they don't want it.  See bug 175104 comment 24 (I really should have duped this to that bug).  However, if a site uses hidden iframes to load the page instead, it isn't easily filtered, so by actually using the prefetch feature site admins gain control over prefetch-style loading.

There are sites that actually use this feature the way it was intended (i.e. a multiple page news story prefetches the next page), and disabling it because there appears to be a bug based solely on anecdotal evidence is an extremely flawed argument.  There are leak tools that can be enabled in nightlies, test with those,  report the leak, get it fixed.  Only if we can't fix it would disabling it be a viable path.