The downloadable diff for the review is 1.6MB.

The review has 138 different files (7 pages).

Page 1 loads in ~1 minute in FireFox. The twenty files are on average
38 K. (max=118K, min=2K). Here all files have edit changes (no deleted

Page 3 loads in ~3 minutes in FireFox. The twenty files are on average
25K . No major deviations from the average. Here 12 of the files have
been deleted rather than just edited.

There are hundreds of review comments on this review across many users
and files.

During page load, the CPU is pegged and the browser is unresponsive
for a good 2-3 minutes. This is the cause every time, very
reproducable. If you are patient the page finally loads and the system
CPU returns to normal.

FireBug shows an HTTPS GET request for each of the twenty files during
the slow down/cpu pegging. Each HTTPS GETS are taking longer on page
3, with some taking up to 2.5 seconds (others < 50ms). Since the is
cpu is pegged the browser processing seems to be the cause of the
delay however.

On Mar 16, 6:31 pm, Christian Hammond <> wrote:
> So it's really going to depend on the sizes of the individual files
> themselves. If a file is by itself large enough to cause a couple meg diff
> to be generated, there's nothing we can do really do, since that boils down
> to too large a file to show in the browser.
> In your page 3 example, how big are the files and the diffs in particular?
> The page itself loads quick enough, right? It's just the diff fragments?
> Which ones are you finding takes a long time and how big are those changes?
> Christian
> --
> Christian Hammond -
> Review Board -
> VMware, Inc. -
> On Mon, Mar 16, 2009 at 5:32 PM, mary <> wrote:
> > On really large diffs, performance is very slow and can crash the
> > browser.
> > We've picked up the recent 3/13/09 nightly which has helped enormously
> > (A BIG THANKS!) but that said, we're still finding pages that take 3+
> > minutes to load.
> > For example.... we have one review in particular that has File Changes
> > spread over 6 ReviewBoard pages. Page 3 takes on average 3+ minutes to
> > load. It also readily crashes my browser - pegging my CPU and I have
> > to kill the session. (URL=https://reviewboard/r/2808/diff/?page=3).
> > This is in FireFox 3.0.7. Under IE the page doesn't load without
> > running into script errors. Unfortunately, these large ReviewBoard
> > diffs are a typical use case at our company (typically when large
> > merges are done) and breaking things across more than 10 reviews jsut
> > isn't plausible. I should mention that not only are the diff fragments
> > themselves large for these use cases but the number of reviewers and
> > comments gets to be very large too. We're maxing out what ReviewBoard
> > can handle on all fronts.
> > Can further investigation be done into these performance issues for
> > us? I will supply further information as I collect it.
> > Thanks,
> > Mary- Hide quoted text -
> - Show quoted text -
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