changegroup: compute seen files as changesets are added (
issue4750)
Before this patch, addchangegroup() would walk the changelog and compute
the set of seen files between applying changesets and applying
manifests. When cloning large repositories such as mozilla-central,
this consumed a non-trivial amount of time. On my MBP, this walk takes
~10s. On a dainty EC2 instance, this was measured to take ~125s! On the
latter machine, this delay was enough for the Mercurial server to
disconnect the client, thinking it had timed out, thus causing a clone
to abort.
This patch enables the changelog to compute the set of changed files as
new revisions are added. By doing so, we:
* avoid a potentially heavy computation between changelog and manifest
processing by spreading the computation across all changelog additions
* avoid extra reads from the changelog by operating on the data as it is
added
The downside of this is that the add revision callback does result in
extra I/O. Before, we would perform a flush (and subsequent read to
construct the full revision) when new delta chains were created. For
changelogs, this is typically every 2-4 revisions. Using the callback
guarantees there will be a flush after every added revision *and* an
open + read of the changelog to obtain the full revision in order to
read the added files. So, this increases the frequency of these
operations by the average chain length. In the future, the revlog
should be smart enough to know how to read revisions that haven't been
flushed yet, thus eliminating this extra I/O.
On my MBP, the total CPU times for an `hg unbundle` with a local
mozilla-central gzip bundle containing 251,934 changesets and 211,065
files did not have a statistically significant change with this patch,
holding steady around 360s. So, the increased revlog flushing did not
have an effect.
With this patch, there is no longer a visible pause between applying
changeset and manifest data. Before, it sure felt like Mercurial was
lethargic making this transition. Now, the transition is nearly
instantaneous, giving the impression that Mercurial is faster. Of course,
eliminating this pause means that the potential for network disconnect due
to channel inactivity during the changelog walk is eliminated as well.
And that is the impetus behind this change.
$ . "$TESTDIR/bzr-definitions"
create and rename on the same file in the same step
$ mkdir test-createandrename
$ cd test-createandrename
$ bzr init -q source
test empty repo conversion (issue3233)
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
back to the rename stuff
$ cd source
$ echo a > a
$ echo c > c
$ echo e > e
$ bzr add -q a c e
$ bzr commit -q -m 'Initial add: a, c, e'
$ bzr mv a b
a => b
$ bzr mv c d
c => d
$ bzr mv e f
e => f
$ echo a2 >> a
$ mkdir e
$ bzr add -q a e
$ bzr commit -q -m 'rename a into b, create a, rename c into d'
$ cd ..
$ hg convert source source-hg
scanning source...
sorting...
converting...
1 Initial add: a, c, e
0 rename a into b, create a, rename c into d
$ glog -R source-hg
o 1@source "rename a into b, create a, rename c into d" files: a b c d e f
|
o 0@source "Initial add: a, c, e" files: a c e
manifest
$ hg manifest -R source-hg -r tip
a
b
d
f
test --rev option
$ hg convert -r 1 source source-1-hg
initializing destination source-1-hg repository
scanning source...
sorting...
converting...
0 Initial add: a, c, e
$ glog -R source-1-hg
o 0@source "Initial add: a, c, e" files: a c e
test with filemap
$ cat > filemap <<EOF
> exclude a
> EOF
$ hg convert --filemap filemap source source-filemap-hg
initializing destination source-filemap-hg repository
scanning source...
sorting...
converting...
1 Initial add: a, c, e
0 rename a into b, create a, rename c into d
$ hg -R source-filemap-hg manifest -r tip
b
d
f
convert from lightweight checkout
$ bzr checkout --lightweight source source-light
$ hg convert -s bzr source-light source-light-hg
initializing destination source-light-hg repository
warning: lightweight checkouts may cause conversion failures, try with a regular branch instead.
$TESTTMP/test-createandrename/source-light does not look like a Bazaar repository
abort: source-light: missing or unsupported repository
[255]
extract timestamps that look just like hg's {date|isodate}:
yyyy-mm-dd HH:MM zzzz (no seconds!)
compare timestamps
$ cd source
$ bzr log | \
> sed '/timestamp/!d;s/.\{15\}\([0-9: -]\{16\}\):.. \(.[0-9]\{4\}\)/\1 \2/' \
> > ../bzr-timestamps
$ cd ..
$ hg -R source-hg log --template "{date|isodate}\n" > hg-timestamps
$ cmp bzr-timestamps hg-timestamps || diff -u bzr-timestamps hg-timestamps
$ cd ..
merge
$ mkdir test-merge
$ cd test-merge
$ cat > helper.py <<EOF
> import sys
> from bzrlib import workingtree
> wt = workingtree.WorkingTree.open('.')
>
> message, stamp = sys.argv[1:]
> wt.commit(message, timestamp=int(stamp))
> EOF
$ bzr init -q source
$ cd source
$ echo content > a
$ echo content2 > b
$ bzr add -q a b
$ bzr commit -q -m 'Initial add'
$ cd ..
$ bzr branch -q source source-improve
$ cd source
$ echo more >> a
$ python ../helper.py 'Editing a' 100
$ cd ../source-improve
$ echo content3 >> b
$ python ../helper.py 'Editing b' 200
$ cd ../source
$ bzr merge -q ../source-improve
$ bzr commit -q -m 'Merged improve branch'
$ cd ..
$ hg convert --datesort source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
3 Initial add
2 Editing a
1 Editing b
0 Merged improve branch
$ glog -R source-hg
o 3@source "Merged improve branch" files:
|\
| o 2@source-improve "Editing b" files: b
| |
o | 1@source "Editing a" files: a
|/
o 0@source "Initial add" files: a b
$ cd ..
#if symlink execbit
symlinks and executable files
$ mkdir test-symlinks
$ cd test-symlinks
$ bzr init -q source
$ cd source
$ touch program
$ chmod +x program
$ ln -s program altname
$ mkdir d
$ echo a > d/a
$ ln -s a syma
$ bzr add -q altname program syma d/a
$ bzr commit -q -m 'Initial setup'
$ touch newprog
$ chmod +x newprog
$ rm altname
$ ln -s newprog altname
$ chmod -x program
$ bzr add -q newprog
$ bzr commit -q -m 'Symlink changed, x bits changed'
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Initial setup
0 Symlink changed, x bits changed
$ manifest source-hg 0
% manifest of 0
644 @ altname
644 d/a
755 * program
644 @ syma
$ manifest source-hg tip
% manifest of tip
644 @ altname
644 d/a
755 * newprog
644 program
644 @ syma
test the symlinks can be recreated
$ cd source-hg
$ hg up
5 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg cat syma; echo
a
$ cd ../..
#endif
Multiple branches
$ bzr init-repo -q --no-trees repo
$ bzr init -q repo/trunk
$ bzr co repo/trunk repo-trunk
$ cd repo-trunk
$ echo a > a
$ bzr add -q a
$ bzr ci -qm adda
$ bzr tag trunk-tag
Created tag trunk-tag.
$ bzr switch -b branch
Tree is up to date at revision 1.
Switched to branch: *repo/branch/ (glob)
$ sleep 1
$ echo b > b
$ bzr add -q b
$ bzr ci -qm addb
$ bzr tag branch-tag
Created tag branch-tag.
$ bzr switch --force ../repo/trunk
Updated to revision 1.
Switched to branch: */repo/trunk/ (glob)
$ sleep 1
$ echo a >> a
$ bzr ci -qm changea
$ cd ..
$ hg convert --datesort repo repo-bzr
initializing destination repo-bzr repository
scanning source...
sorting...
converting...
2 adda
1 addb
0 changea
updating tags
$ (cd repo-bzr; glog)
o 3@default "update tags" files: .hgtags
|
o 2@default "changea" files: a
|
| o 1@branch "addb" files: b
|/
o 0@default "adda" files: a
Test tags (converted identifiers are not stable because bzr ones are
not and get incorporated in extra fields).
$ hg -R repo-bzr tags
tip 3:* (glob)
branch-tag 1:* (glob)
trunk-tag 0:* (glob)
Nested repositories (issue3254)
$ bzr init-repo -q --no-trees repo/inner
$ bzr init -q repo/inner/trunk
$ bzr co repo/inner/trunk inner-trunk
$ cd inner-trunk
$ echo b > b
$ bzr add -q b
$ bzr ci -qm addb
$ cd ..
$ hg convert --datesort repo noinner-bzr
initializing destination noinner-bzr repository
scanning source...
sorting...
converting...
2 adda
1 addb
0 changea
updating tags