largefiles: optimize update speed by only updating changed largefiles
Historically, during 'hg update', every largefile in the working copy was
hashed (which is a very expensive operation on big files) and any
largefiles that did not have a hash that matched their standin were
updated.
This patch optimizes 'hg update' by keeping track of what standins have
changed between the old and new revisions, and only updating the largefiles
that have changed. This saves a lot of time by avoiding the unecessary
calculation of a list of sha1 hashes for big files.
With this patch, the time 'hg update' takes to complete is a function of
how many largefiles need to be updated and what their size is.
Performance tests on a repository with about 80 largefiles ranging from
a few MB to about 97 MB are shown below. The tests show how long it takes
to run 'hg update' with no changes actually being updated.
Mercurial 2.1 release:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
0 largefiles updated, 0 removed
real 0m10.045s
user 0m9.367s
sys 0m0.674s
With this patch:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
real 0m0.965s
user 0m0.845s
sys 0m0.115s
The same repsoitory, without the largefiles extension enabled:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
real 0m0.799s
user 0m0.684s
sys 0m0.111s
So before the patch, 'hg update' with no changes was approximately 9.25s
slower with largefiles enabled. With this patch, it is approximately 0.165s
slower.
Use hgrc within $TESTTMP
$ HGRCPATH=`pwd`/hgrc
$ export HGRCPATH
Use an alternate var for scribbling on hgrc to keep check-code from
complaining about the important settings we may be overwriting:
$ HGRC=`pwd`/hgrc
$ export HGRC
Basic syntax error
$ echo "invalid" > $HGRC
$ hg version
hg: parse error at $TESTTMP/hgrc:1: invalid
[255]
$ echo "" > $HGRC
Issue1199: Can't use '%' in hgrc (eg url encoded username)
$ hg init "foo%bar"
$ hg clone "foo%bar" foobar
updating to branch default
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd foobar
$ cat .hg/hgrc
[paths]
default = $TESTTMP/foo%bar (glob)
$ hg paths
default = $TESTTMP/foo%bar (glob)
$ hg showconfig
bundle.mainreporoot=$TESTTMP/foobar (glob)
paths.default=$TESTTMP/foo%bar (glob)
$ cd ..
issue1829: wrong indentation
$ echo '[foo]' > $HGRC
$ echo ' x = y' >> $HGRC
$ hg version
hg: parse error at $TESTTMP/hgrc:2: x = y
[255]
$ python -c "print '[foo]\nbar = a\n b\n c \n de\n fg \nbaz = bif cb \n'" \
> > $HGRC
$ hg showconfig foo
foo.bar=a\nb\nc\nde\nfg
foo.baz=bif cb
$ FAKEPATH=/path/to/nowhere
$ export FAKEPATH
$ echo '%include $FAKEPATH/no-such-file' > $HGRC
$ hg version
Mercurial Distributed SCM (version *) (glob)
(see http://mercurial.selenic.com for more information)
Copyright (C) 2005-2012 Matt Mackall and others
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ unset FAKEPATH
make sure global options given on the cmdline take precedence
$ hg showconfig --config ui.verbose=True --quiet
ui.verbose=False
ui.debug=False
ui.quiet=True
$ touch foobar/untracked
$ cat >> foobar/.hg/hgrc <<EOF
> [ui]
> verbose=True
> EOF
$ hg -R foobar st -q
username expansion
$ olduser=$HGUSER
$ unset HGUSER
$ FAKEUSER='John Doe'
$ export FAKEUSER
$ echo '[ui]' > $HGRC
$ echo 'username = $FAKEUSER' >> $HGRC
$ hg init usertest
$ cd usertest
$ touch bar
$ hg commit --addremove --quiet -m "added bar"
$ hg log --template "{author}\n"
John Doe
$ cd ..
$ hg showconfig
ui.username=$FAKEUSER
$ unset FAKEUSER
$ HGUSER=$olduser
$ export HGUSER
showconfig with multiple arguments
$ echo "[alias]" > $HGRC
$ echo "log = log -g" >> $HGRC
$ echo "[defaults]" >> $HGRC
$ echo "identify = -n" >> $HGRC
$ hg showconfig alias defaults
alias.log=log -g
defaults.identify=-n
$ hg showconfig alias defaults.identify
abort: only one config item permitted
[255]
$ hg showconfig alias.log defaults.identify
abort: only one config item permitted
[255]
HGPLAIN
$ cd ..
$ p=`pwd`
$ echo "[ui]" > $HGRC
$ echo "debug=true" >> $HGRC
$ echo "fallbackencoding=ASCII" >> $HGRC
$ echo "quiet=true" >> $HGRC
$ echo "slash=true" >> $HGRC
$ echo "traceback=true" >> $HGRC
$ echo "verbose=true" >> $HGRC
$ echo "style=~/.hgstyle" >> $HGRC
$ echo "logtemplate={node}" >> $HGRC
$ echo "[defaults]" >> $HGRC
$ echo "identify=-n" >> $HGRC
$ echo "[alias]" >> $HGRC
$ echo "log=log -g" >> $HGRC
customized hgrc
$ hg showconfig
read config from: $TESTTMP/hgrc
$TESTTMP/hgrc:13: alias.log=log -g
$TESTTMP/hgrc:11: defaults.identify=-n
$TESTTMP/hgrc:2: ui.debug=true
$TESTTMP/hgrc:3: ui.fallbackencoding=ASCII
$TESTTMP/hgrc:4: ui.quiet=true
$TESTTMP/hgrc:5: ui.slash=true
$TESTTMP/hgrc:6: ui.traceback=true
$TESTTMP/hgrc:7: ui.verbose=true
$TESTTMP/hgrc:8: ui.style=~/.hgstyle
$TESTTMP/hgrc:9: ui.logtemplate={node}
plain hgrc
$ HGPLAIN=; export HGPLAIN
$ hg showconfig --config ui.traceback=True --debug
read config from: $TESTTMP/hgrc
none: ui.traceback=True
none: ui.verbose=False
none: ui.debug=True
none: ui.quiet=False
plain mode with exceptions
$ cat > plain.py <<EOF
> def uisetup(ui):
> ui.write('plain: %r\n' % ui.plain())
> EOF
$ echo "[extensions]" >> $HGRC
$ echo "plain=./plain.py" >> $HGRC
$ HGPLAINEXCEPT=; export HGPLAINEXCEPT
$ hg showconfig --config ui.traceback=True --debug
plain: True
read config from: $TESTTMP/hgrc
$TESTTMP/hgrc:15: extensions.plain=./plain.py
none: ui.traceback=True
none: ui.verbose=False
none: ui.debug=True
none: ui.quiet=False
$ unset HGPLAIN
$ hg showconfig --config ui.traceback=True --debug
plain: True
read config from: $TESTTMP/hgrc
$TESTTMP/hgrc:15: extensions.plain=./plain.py
none: ui.traceback=True
none: ui.verbose=False
none: ui.debug=True
none: ui.quiet=False
$ HGPLAINEXCEPT=i18n; export HGPLAINEXCEPT
$ hg showconfig --config ui.traceback=True --debug
plain: True
read config from: $TESTTMP/hgrc
$TESTTMP/hgrc:15: extensions.plain=./plain.py
none: ui.traceback=True
none: ui.verbose=False
none: ui.debug=True
none: ui.quiet=False