simple plugin to speed things up

[Denys Duchier]

I wrote my first plugin:

             http://delta.univ-orleans.fr/~duchier/bzr/plugin.cache

It does 2 things:

1. it provides the command "bzr cache" to populate a cache with inventory
   pickles for the revision history.

2. it automatically causes bzr to use this cache first, and only hit the weave
   if no pickle is available for the revision sought.

Here are some benchmarks:

$ time bzr --no-plugins log NEWS >/dev/null

real    4m31.447s
user    4m28.962s
sys     0m1.793s

$ time bzr.cleanup --no-plugins log NEWS >/dev/null

real    2m26.561s
user    2m25.130s
sys     0m1.056s

$ time bzr log NEWS >/dev/null

real    0m47.043s
user    0m45.336s
sys     0m1.499s

$ time bzr.cleanup log NEWS >/dev/null

real    0m37.725s
user    0m36.529s
sys     0m0.937s

and the size of the cache for bzr.dev:

$ du -sh .bzr/inventory-cache
76M     .bzr/inventory-cache

when you need the disk space, just blow away .bzr/inventory-cache.  The cache is
never populated automatically, you have to invoked "bzr cache".

Cheers,

--Denys