Libraries in the repo

[Simon Marlow]

Duncan Coutts wrote:
> On Fri, 2009-08-28 at 11:42 +0100, Simon Marlow wrote:
> 
>> Can anyone think of a good reason not to upgrade darcs to 2.3.0 on 
>> darcs.haskell.org?  I can think of 3 reasons to do so:
>>
>>   - this script, for preventing accidental divergence from upstream
>>   - faster pushes, due to transfer-mode
>>   - hide those annoying "Ignore-this: xxxxx" messages
> 
> By the way, people who regularly work with the ghc repos (at least on
> Linux) and who are thinking of upgrading to darcs-2.3.0 should heed this
> advice:
> 
>         Use "darcs get" to get your repos again. Not remotely, just
>         locally. This switches them from darcs1 traditional format to
>         darcs1 hashed format.
>         
>         If you do this, then "darcs whatsnew" gets ~4 times quicker.
>         If you do not do this, then "darcs whatsnew" gets ~100 times
>         slower.
>         
> All times measured on Linux, local ext3 filesystem, ghc testsuite repo.
> All times are the second of two runs to allow for OS caching. The
> results may well be quite different on a different file systems, like
> Windows NTFS.

yes - on Windows things got slower with 2.3.0, even with hashed 
repositories:

http://bugs.darcs.net/issue1585

Another thing to watch out for is that hashed repositories will 
automatically cache patches and pristine files in ~/.darcs/cache by 
default.  If you home directory is NFS-mounted, this can be a bad idea. 
  Even if you're not using NFS, the fact that pristine files are shared 
between all repositories means that darcs sometimes is a lot slower than 
it needs to be, because the timestamps on the pristine files are out of 
sync with the local repository (you'll see long "Reading pristine..." 
messages from darcs).  I raised this on the darcs-users list before the 
2.3.0 release, but as far as I know it isn't planned to be fixed until 2.4.

Cheers,
	Simon