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.
$ cat <<EOF >> $HGRCPATH
> [extensions]
> notify=
>
> [hooks]
> changegroup.notify = python:hgext.notify.hook
>
> [notify]
> sources = push
> diffstat = False
> maxsubject = 10
>
> [usersubs]
> foo@bar = *
>
> [reposubs]
> * = baz
> EOF
$ hg init a
clone
$ hg --traceback clone a b
updating to branch default
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo a > b/a
commit
$ hg --traceback --cwd b commit -Ama
adding a
$ echo a >> b/a
commit
$ hg --traceback --cwd b commit -Amb
push
$ hg --traceback --cwd b push ../a 2>&1 |
> $PYTHON -c 'import sys,re; print re.sub("\n\t", " ", sys.stdin.read()),'
pushing to ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Date: * (glob)
Subject: * (glob)
From: test
X-Hg-Notification: changeset cb9a9f314b8b
Message-Id: <*> (glob)
To: baz, foo@bar
changeset cb9a9f314b8b in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=cb9a9f314b8b
summary: a
changeset ba677d0156c1 in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=ba677d0156c1
summary: b
diffs (6 lines):
diff -r 000000000000 -r ba677d0156c1 a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,2 @@
+a
+a
$ hg --cwd a rollback
repository tip rolled back to revision -1 (undo push)
unbundle with unrelated source
$ hg --cwd b bundle ../test.hg ../a
searching for changes
2 changesets found
$ hg --cwd a unbundle ../test.hg
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
(run 'hg update' to get a working copy)
$ hg --cwd a rollback
repository tip rolled back to revision -1 (undo unbundle)
unbundle with correct source
$ hg --config notify.sources=unbundle --cwd a unbundle ../test.hg 2>&1 |
> $PYTHON -c 'import sys,re; print re.sub("\n\t", " ", sys.stdin.read()),'
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Date: * (glob)
Subject: * (glob)
From: test
X-Hg-Notification: changeset cb9a9f314b8b
Message-Id: <*> (glob)
To: baz, foo@bar
changeset cb9a9f314b8b in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=cb9a9f314b8b
summary: a
changeset ba677d0156c1 in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=ba677d0156c1
summary: b
diffs (6 lines):
diff -r 000000000000 -r ba677d0156c1 a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,2 @@
+a
+a
(run 'hg update' to get a working copy)
Check that using the first committer as the author of a changeset works:
Check that the config option works.
Check that the first committer is indeed used for "From:".
Check that the merge user is NOT used for "From:"
Create new file
$ echo a > b/b
$ echo b >> b/b
$ echo c >> b/b
$ hg --traceback --cwd b commit -Amnewfile -u committer_1
adding b
commit as one user
$ echo x > b/b
$ echo b >> b/b
$ echo c >> b/b
$ hg --traceback --cwd b commit -Amx -u committer_2
commit as other user, change file so we can do an (automatic) merge
$ hg --cwd b up 2
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo a > b/b
$ echo b >> b/b
$ echo y >> b/b
$ hg --traceback --cwd b commit -Amy -u committer_3
created new head
merge as a different user
$ hg --cwd b merge --config notify.fromauthor=True
merging b
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg --traceback --cwd b commit -Am "merged"
push
$ hg --traceback --cwd b --config notify.fromauthor=True push ../a 2>&1 |
> $PYTHON -c 'import sys,re; print re.sub("\n\t", " ", sys.stdin.read()),'
pushing to ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 4 changesets with 4 changes to 1 files
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Date: * (glob)
Subject: * (glob)
From: committer_1
X-Hg-Notification: changeset 84e487dddc58
Message-Id: <*> (glob)
To: baz, foo@bar
changeset 84e487dddc58 in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=84e487dddc58
summary: newfile
changeset b29c7a2b6b0c in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=b29c7a2b6b0c
summary: x
changeset 0957c7d64886 in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=0957c7d64886
summary: y
changeset 485b4e6b0249 in $TESTTMP/a (glob)
details: $TESTTMP/a?cmd=changeset;node=485b4e6b0249
summary: merged
diffs (7 lines):
diff -r ba677d0156c1 -r 485b4e6b0249 b
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/b Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,3 @@
+x
+b
+y
$ hg --cwd a rollback
repository tip rolled back to revision 1 (undo push)