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.
#require svn svn-bindings
$ cat >> $HGRCPATH <<EOF
> [extensions]
> convert =
> EOF
$ svnadmin create svn-repo
$ svnadmin load -q svn-repo < "$TESTDIR/svn/move.svndump"
$ SVNREPOPATH=`pwd`/svn-repo
#if windows
$ SVNREPOURL=file:///`$PYTHON -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#else
$ SVNREPOURL=file://`$PYTHON -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#endif
Convert trunk and branches
$ hg convert --datesort "$SVNREPOURL"/subproject A-hg
initializing destination A-hg repository
scanning source...
sorting...
converting...
13 createtrunk
12 moved1
11 moved1
10 moved2
9 changeb and rm d2
8 changeb and rm d2
7 moved1again
6 moved1again
5 copyfilefrompast
4 copydirfrompast
3 add d3
2 copy dir and remove subdir
1 add d4old
0 rename d4old into d4new
$ cd A-hg
$ hg log -G --template '{rev} {desc|firstline} files: {files}\n'
o 13 rename d4old into d4new files: d4new/g d4old/g
|
o 12 add d4old files: d4old/g
|
o 11 copy dir and remove subdir files: d3/d31/e d4/d31/e d4/f
|
o 10 add d3 files: d3/d31/e d3/f
|
o 9 copydirfrompast files: d2/d
|
o 8 copyfilefrompast files: d
|
o 7 moved1again files: d1/b d1/c
|
| o 6 moved1again files:
| |
o | 5 changeb and rm d2 files: d1/b d2/d
| |
| o 4 changeb and rm d2 files: b
| |
o | 3 moved2 files: d2/d
| |
o | 2 moved1 files: d1/b d1/c
| |
| o 1 moved1 files: b c
|
o 0 createtrunk files:
Check move copy records
$ hg st --rev 12:13 --copies
A d4new/g
d4old/g
R d4old/g
Check branches
$ hg branches
default 13:* (glob)
d1 6:* (glob)
$ cd ..
$ mkdir test-replace
$ cd test-replace
$ svnadmin create svn-repo
$ svnadmin load -q svn-repo < "$TESTDIR/svn/replace.svndump"
Convert files being replaced by directories
$ hg convert svn-repo hg-repo
initializing destination hg-repo repository
scanning source...
sorting...
converting...
6 initial
5 clobber symlink
4 clobber1
3 clobber2
2 adddb
1 clobberdir
0 branch
$ cd hg-repo
Manifest before
$ hg -v manifest -r 1
644 a
644 d/b
644 d2/a
644 @ dlink
644 @ dlink2
644 dlink3
Manifest after clobber1
$ hg -v manifest -r 2
644 a/b
644 d/b
644 d2/a
644 dlink/b
644 @ dlink2
644 dlink3
Manifest after clobber2
$ hg -v manifest -r 3
644 a/b
644 d/b
644 d2/a
644 dlink/b
644 @ dlink2
644 @ dlink3
Manifest after clobberdir
$ hg -v manifest -r 6
644 a/b
644 d/b
644 d2/a
644 d2/c
644 dlink/b
644 @ dlink2
644 @ dlink3
Try updating
$ hg up -qC default
$ cd ..
Test convert progress bar
$ cat >> $HGRCPATH <<EOF
> [extensions]
> progress =
> [progress]
> assume-tty = 1
> delay = 0
> changedelay = 0
> format = topic bar number
> refresh = 0
> width = 60
> EOF
$ hg convert svn-repo hg-progress
\r (no-eol) (esc)
scanning [=====> ] 1/7\r (no-eol) (esc)
scanning [===========> ] 2/7\r (no-eol) (esc)
scanning [=================> ] 3/7\r (no-eol) (esc)
scanning [========================> ] 4/7\r (no-eol) (esc)
scanning [==============================> ] 5/7\r (no-eol) (esc)
scanning [====================================> ] 6/7\r (no-eol) (esc)
scanning [===========================================>] 7/7\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [ ] 0/7\r (no-eol) (esc)
getting files [=====> ] 1/6\r (no-eol) (esc)
getting files [============> ] 2/6\r (no-eol) (esc)
getting files [==================> ] 3/6\r (no-eol) (esc)
getting files [=========================> ] 4/6\r (no-eol) (esc)
getting files [===============================> ] 5/6\r (no-eol) (esc)
getting files [======================================>] 6/6\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=====> ] 1/7\r (no-eol) (esc)
scanning paths [ ] 0/1\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [===========> ] 2/7\r (no-eol) (esc)
scanning paths [ ] 0/2\r (no-eol) (esc)
scanning paths [==================> ] 1/2\r (no-eol) (esc)
getting files [========> ] 1/4\r (no-eol) (esc)
getting files [==================> ] 2/4\r (no-eol) (esc)
getting files [============================> ] 3/4\r (no-eol) (esc)
getting files [======================================>] 4/4\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=================> ] 3/7\r (no-eol) (esc)
scanning paths [ ] 0/1\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=======================> ] 4/7\r (no-eol) (esc)
scanning paths [ ] 0/1\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=============================> ] 5/7\r (no-eol) (esc)
scanning paths [ ] 0/1\r (no-eol) (esc)
getting files [===> ] 1/8\r (no-eol) (esc)
getting files [========> ] 2/8\r (no-eol) (esc)
getting files [=============> ] 3/8\r (no-eol) (esc)
getting files [==================> ] 4/8\r (no-eol) (esc)
getting files [=======================> ] 5/8\r (no-eol) (esc)
getting files [============================> ] 6/8\r (no-eol) (esc)
getting files [=================================> ] 7/8\r (no-eol) (esc)
getting files [======================================>] 8/8\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [===================================> ] 6/7\r (no-eol) (esc)
scanning paths [ ] 0/3\r (no-eol) (esc)
scanning paths [===========> ] 1/3\r (no-eol) (esc)
scanning paths [========================> ] 2/3\r (no-eol) (esc)
getting files [===> ] 1/8\r (no-eol) (esc)
getting files [========> ] 2/8\r (no-eol) (esc)
getting files [=============> ] 3/8\r (no-eol) (esc)
getting files [==================> ] 4/8\r (no-eol) (esc)
getting files [=======================> ] 5/8\r (no-eol) (esc)
getting files [============================> ] 6/8\r (no-eol) (esc)
getting files [=================================> ] 7/8\r (no-eol) (esc)
getting files [======================================>] 8/8\r (no-eol) (esc)
\r (no-eol) (esc)
initializing destination hg-progress repository
scanning source...
sorting...
converting...
6 initial
5 clobber symlink
4 clobber1
3 clobber2
2 adddb
1 clobberdir
0 branch
$ cd ..