hg slow on large repo

[Brendan Cully]

On Wednesday, 23 May 2007 at 09:17, Benjamin LaHaise wrote:
> Hello,
> 
> I've been investigating the various tools available for migrating a large 
> (11GB) cvs repository into.  After running cvs20hg for a rather long period 
> of time, I now have in my hands a moderately (4.1GB) sized hg repository.
> 
> Now I try to do a clone.  It takes about 15 minutes at 100% CPU utilisation, 
> which is pretty much a non-starter for usability.  The disk isn't anywhere 
> near being saturated.
> 
> Are there any features/tricks that can speed things up?

I'm coming to this late, but my overlay repository patches might help
a bit here:

http://www.selenic.com/mercurial/wiki/index.cgi/OverlayRepository

an overlay of tip can be created with one 64-byte index file in the
store, so it'd save the 4m30s cold cache cost of hardlinking.

I don't think it'd be too hard to let overlays use bundles (similar to
git packs) as parent repositories, which should improve readahead
during the checkout phase. I'll see if I can find some time to try it
out...