'bzr branches' is pathologically slow with an svn+ssh URL

[Glyph Lefkowitz]

$ time svn ls svn+ssh://svn.twistedmatrix.com/svn/Twisted/branches > /dev/null

real 0m1.724s
user 0m0.014s
sys 0m0.015s

$ time bzr branches svn+ssh://svn.twistedmatrix.com/svn/Twisted/branches > /dev/null

...

Actually I got tired of waiting after about three hours and just filed the bug.

It did lots of work in the meanwhile, though.

[Jelmer Vernooij (jelmer)]

  affects bzr-svn
  status triaged
  importance medium

  affects bzr
  status triaged
  medium

On Sun, 2010-11-07 at 02:03 +0000, Glyph Lefkowitz wrote:
> $ time svn ls svn+ssh://svn.twistedmatrix.com/svn/Twisted/branches > /dev/null
>
> real 0m1.724s
> user 0m0.014s
> sys 0m0.015s
>
> $ time bzr branches svn+ssh://svn.twistedmatrix.com/svn/Twisted/branches
> > /dev/null
>
> ...
>
> Actually I got tired of waiting after about three hours and just filed
> the bug.
>
> It did lots of work in the meanwhile, though.
This is caused by the way in which BzrDir.find_branches(transport)
works. It finds all possible control directories first and then filters
out the ones that have a branch attached to them.

In svn, where every directory is a possible control directory, this
doesn't work.

bzr-svn already has a list of branches readily available for each
repository, so it should be able to answer this question without a scan
for branches.

So it would be nice if bzr-svn could provide bzr with the list of
branches under a particular location. I'm not sure what the best way to
do that (in terms of API) is though.

Cheers,

Jelmer

[Jelmer Vernooij (jelmer)]

This is fixed with bzr-svn 1.1.0 and the new "bzr branches" command in bzr.dev. For example, running "bzr branches" against the gcc repository:

charis:~/src/bzr-svn/unstable% time bzr branches svn://gcc.gnu.org/svn/gcc
[273 lines of output]
bzr branches svn://gcc.gnu.org/svn/gcc 0.22s user 0.05s system 8% cpu 3.161 total

[John A Meinel (jameinel)]

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On 8/26/2011 8:05 PM, Jelmer Vernooij wrote:
> This is fixed with bzr-svn 1.1.0 and the new "bzr branches" command
> in bzr.dev. For example, running "bzr branches" against the gcc
> repository:
>
> charis:~/src/bzr-svn/unstable% time bzr branches
> svn://gcc.gnu.org/svn/gcc [273 lines of output] bzr branches
> svn://gcc.gnu.org/svn/gcc 0.22s user 0.05s system 8% cpu 3.161
> total
>
That says 3s to do 'branches'. I'm not sure what you are expecting. It
seems like there is some room for improvement, but you're still
accessing a remote machine there.

John
=:->

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[Jelmer Vernooij (jelmer)]

Yeah, I'm considering this one fixed. Previously that operation took several *hours*.

[Jelmer Vernooij (jelmer)]

It's still not great for twisted, but a lot better (70 seconds) than several hours.

charis:~% time bzr branches svn://svn.twistedmatrix.com/svn/Twisted | wc -l
232
bzr branches svn://svn.twistedmatrix.com/svn/Twisted 0.60s user 0.07s system 0% cpu 1:17.50 total