748125 - Should not cache moz-page-thumb for redirects

Status: RESOLVED WONTFIX

(Firefox :: Tabbed Browser, defect)

Description

[Jason Duell]

I'm seeing we're caching moz-page-thumb entries in the necko cache for HTTP redirects.  I suspect we don't want to do that: it certainly makes no sense for successful redirects (user never sees the content), and a "page moved" body is unlikely to be on anyone's fave list :)

We might want to store a thumbnail image of page that the redirect points to?  But I suspect (not knowing the thumbnail selection code at all) that we'd already keep a thumbnail of that, and hopefully select it for display if it's hit often enough.

Steps to repro:

  Go to 

     http://people.mozilla.com/~jduell/redir

and then check "about:cache" and you'll see there's two entries for the URI: one for the redirect itself (size 0), and one for the thumbnail.

Comment 1

[Jason Duell]

Also, I see we store the moz-page-thumb images without any expiration time.  I'm wondering it this will clog up the HTTP cache more than they are likely to deserve.  Most thumbnail images don't ever get used, correct?  If so it would be nice to set a fairly short expiration time on them, and then extend it only on the ones we're actually using.  If this is a valid issue we should open a separate bug for it.

Comment 2

[Brian Smith (:briansmith, :bsmith, use NEEDINFO?)]

See bug 716949 comment 5:

(In reply to Tim Taubert [:ttaubert] from comment #5)
> (In reply to Brian Smith (:bsmith) from comment #4)
> > (In reply to Tim Taubert [:ttaubert] from comment #0)
> > > Thumbnails are currently stored in the file cache. Unfortunately, the file
> > > cache gets purged way too often (crash, force-quit, clear history [on
> > > shutdown], cache full). We need a way to pin special items (like our
> > > thumbnails) in the cache so that they don't get lost that easily.
> > 
> > I highly recommend that you do not store these in the cache to start with.
> 
> Thank you for your advice. We're going to build a custom thumbnail storage
> in the near future that won't use the file cache.

Comment 3

[Jason Duell]

Then this is WONTFIX