git-codereview: limit reviewer search to last 1000 commits

The vast majority of reviewers are consistently active,
so limiting the search to the last 1000 commits won't
lose many folks. And not loading every commit for a git mail
helps with speed and avoids thrashing the disk cache,
which is a pain point on my slow, spinning platter.

Before, with a warm cache:

$ time git log --format=format:%B | wc -l

real	0m0.860s
user	0m0.398s
sys	0m0.164s

After, with a warm cache:

$ time git log --format=format:%B -n 1000 | wc -l

real	0m0.036s
user	0m0.021s
sys	0m0.021s

Change-Id: Ia56245e6ea05e4ce844d57a6ee96d19453192967
Reviewed-by: Andrew Gerrand <>
1 file changed