bzr-explorer performance question

[Martin Pool]

On 29 June 2010 10:30, Maritza Mendez <martitzam at gmail.com> wrote:
>
> Repeating the original experiment, but from the command line instead of
> bzr-explorer:
>
> bzr init-repo SHARED_REPO
> cd SHARED_REPO
> bzr init trunk
> cd trunk
> # copy all 5000+ files and 300+ directories to trunk
> bzr add   # takes 2.9 seconds
> bzr commit -m "start project"   # takes 142 seconds, very reasonable for the
> work done
> bzr stat  # 22 seconds
> bzr stat  #  less than 1 second
>
>
> So... we see that the first bzr stat after the commit takes much longer than
> the second and third, but still nowhere near the 4.5 minutes typical of the
> first bzr stat in bzr-explorer after the same commit.
>
> Perhaps fstat/lstat is creating a fundamental effect, but something else
> seems to be happening in bzr-explorer.
>
> And to be fair, I should test qbzr as well, since that may be the real
> reason bzr-explorer takes 4.5 minutes.
>
> Meanwhile, I need to think about how to write this up in a bug report.
> Suggestions are welcome.

You can just link to this thread
<https://lists.ubuntu.com/archives/bazaar/2010q2/069122.html> for the
details, but it's nice if you can provide a summary.

It seems to me there are two bugs here:

1- first stat after a commit is unusually slow - I can imagine what's
happening there, specifically that we don't store the file hashes and
stat data during the commit

2- explorer updates are much slower than that - I don't really know
why that would be but perhaps profiling explorer will make it clear

-- 
Martin