view README @ 20894:04e1596d5dbd

revset: improve _descendants performance

Previously revset._descendants would iterate over the entire subset (which is
often the entire repo) and test if each rev was in the descendants list. This is
really slow on large repos (3+ seconds).

Now we iterate over the descendants and test if they're in the subset.
This affects advancing and retracting the phase boundary (3.5 seconds down to
0.8 seconds, which is even faster than it was in 2.9). Also affects commands
that move the phase boundary (commit and rebase, presumably).

The new revsetbenchmark indicates an improvement from 0.2 to 0.12 seconds. So
future revset changes should be able to notice regressions.

I removed a bad test. It was recently added and tested '1:: and reverse(all())',
which has an amibiguous output direction.  Previously it printed in reverse order,
because we iterated over the subset (the reverse part). Now it prints in normal
order because we iterate over the 1:: . Since the revset itself doesn't imply an
order, I removed the test.

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.