revset: remove existence check from min() and max()
min() and max() would first do an existence check. Unfortunately existence
checks can be slow in certain situations (like if the smartset is a list, and
quickly iterable in both ascending and descending directions, then doing an
existence check will start from the bottom, even if you want to check the
max()).
The fix is to not do the check, and just handle the error if it happens. In a
large repo, this speeds up:
hg log -r 'max(parents(. + .^) - (. + .^) & ::master)'
from 3.5s to 0.85s. That revset is contrived and just for testing. In our
real case we used 'bundle()' in place of '. + .^'
Interesting perf numbers for the revset benchmarks:
max(draft() and ::tip) => 0.027s to 0.0005s
max(author(lmoscovicz)) => 2.48s to 0.57s
min doesn't show any perf changes, but changing it as well will prevent a perf
regression in my next patch.
Result from revset benchmark
revset #0: draft() and ::tip
min max
0) 0.001971 0.001991
1) 0.001965 0.000428 21%
revset #1: ::tip and draft()
min max
0) 0.002017 0.001912
1) 0.001896 94% 0.000421 22%
revset #2: author(lmoscovicz)
min max
0) 1.049033 1.358913
1) 1.042508 0.319824 23%
revset #3: author(lmoscovicz) or author(mpm)
min max
0) 1.042512 1.367432
1) 1.019750 0.327750 23%
revset #4: author(mpm) or author(lmoscovicz)
min max
0) 1.050135 0.324924
1) 1.070698 0.319913
revset #5: roots((tip~100::) - (tip~100::tip))
min max
0) 0.000671 0.001018
1) 0.000605 90% 0.000946 92%
revset #6: roots((0::) - (0::tip))
min max
0) 0.149714 0.152369
1) 0.098677 65% 0.100374 65%
revset #7: (20000::) - (20000)
min max
0) 0.051019 0.042747
1) 0.035586 69% 0.016267 38%
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing:
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.