Mercurial > hg
view tests/test-rollback.t @ 30764:e75463e3179f
protocol: send application/mercurial-0.2 responses to capable clients
With this commit, the HTTP transport now parses the X-HgProto-<N>
header to determine what media type and compression engine to use for
responses. So far, we only compress responses that are already being
compressed with zlib today (stream response types to specific
commands). We can expand things to cover additional response types
later.
The practical side-effect of this commit is that non-zlib compression
engines will be used if both ends support them. This means if both
ends have zstd support, zstd - not zlib - will be used to compress
data!
When cloning the mozilla-unified repository between a local HTTP
server and client, the benefits of non-zlib compression are quite
noticeable:
engine server CPU (s) client CPU (s) bundle size
zlib (l=6) 174.1 283.2 1,148,547,026
zstd (l=1) 99.2 267.3 1,127,513,841
zstd (l=3) 103.1 266.9 1,018,861,363
zstd (l=7) 128.3 269.7 919,190,278
zstd (l=10) 162.0 - 894,547,179
none 95.3 277.2 4,097,566,064
The default zstd compression level is 3. So if you deploy zstd
capable Mercurial to your clients and servers and CPU time on
your server is dominated by "getbundle" requests (clients cloning
and pulling) - and my experience at Mozilla tells me this is often
the case - this commit could drastically reduce your server-side
CPU usage *and* save on bandwidth costs!
Another benefit of this change is that server operators can install
*any* compression engine. While it isn't enabled by default, the
"none" compression engine can now be used to disable wire protocol
compression completely. Previously, commands like "getbundle" always
zlib compressed output, adding considerable overhead to generating
responses. If you are on a high speed network and your server is under
high load, it might be advantageous to trade bandwidth for CPU.
Although, zstd at level 1 doesn't use that much CPU, so I'm not
convinced that disabling compression wholesale is worthwhile. And, my
data seems to indicate a slow down on the client without compression.
I suspect this is due to a lack of buffering resulting in an increase
in socket read() calls and/or the fact we're transferring an extra 3 GB
of data (parsing HTTP chunked transfer and processing extra TCP packets
can add up). This is definitely worth investigating and optimizing. But
since the "none" compressor isn't enabled by default, I'm inclined to
punt on this issue.
This commit introduces tons of tests. Some of these should arguably
have been implemented on previous commits. But it was difficult to
test without the server functionality in place.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 24 Dec 2016 15:29:32 -0700 |
parents | fe50341de1ff |
children | 3ed26ba54685 |
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setup repo $ hg init t $ cd t $ echo a > a $ hg commit -Am'add a' adding a $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 1 changesets, 1 total revisions $ hg parents changeset: 0:1f0dee641bb7 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add a rollback to null revision $ hg status $ hg rollback repository tip rolled back to revision -1 (undo commit) working directory now based on revision -1 $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 0 files, 0 changesets, 0 total revisions $ hg parents $ hg status A a Two changesets this time so we rollback to a real changeset $ hg commit -m'add a again' $ echo a >> a $ hg commit -m'modify a' Test issue 902 (current branch is preserved) $ hg branch test marked working directory as branch test (branches are permanent and global, did you want a bookmark?) $ hg rollback repository tip rolled back to revision 0 (undo commit) working directory now based on revision 0 $ hg branch default Test issue 1635 (commit message saved) $ cat .hg/last-message.txt ; echo modify a Test rollback of hg before issue 902 was fixed $ hg commit -m "test3" $ hg branch test marked working directory as branch test (branches are permanent and global, did you want a bookmark?) $ rm .hg/undo.branch $ hg rollback repository tip rolled back to revision 0 (undo commit) named branch could not be reset: current branch is still 'test' working directory now based on revision 0 $ hg branch test working dir unaffected by rollback: do not restore dirstate et. al. $ hg log --template '{rev} {branch} {desc|firstline}\n' 0 default add a again $ hg status M a $ hg bookmark foo $ hg commit -m'modify a again' $ echo b > b $ hg bookmark bar -r default #making bar active, before the transaction $ hg commit -Am'add b' adding b $ hg log --template '{rev} {branch} {desc|firstline}\n' 2 test add b 1 test modify a again 0 default add a again $ hg update bar 1 files updated, 0 files merged, 1 files removed, 0 files unresolved (activating bookmark bar) $ cat .hg/undo.branch ; echo test $ hg rollback -f repository tip rolled back to revision 1 (undo commit) $ hg id -n 0 $ hg branch default $ cat .hg/bookmarks.current ; echo bar $ hg bookmark --delete foo bar rollback by pretxncommit saves commit message (issue1635) $ echo a >> a $ hg --config hooks.pretxncommit=false commit -m"precious commit message" transaction abort! rollback completed abort: pretxncommit hook exited with status * (glob) [255] $ cat .hg/last-message.txt ; echo precious commit message same thing, but run $EDITOR $ cat > editor.sh << '__EOF__' > echo "another precious commit message" > "$1" > __EOF__ $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg --config hooks.pretxncommit=false commit 2>&1 note: commit message saved in .hg/last-message.txt transaction abort! rollback completed abort: pretxncommit hook exited with status * (glob) [255] $ cat .hg/last-message.txt another precious commit message test rollback on served repository #if serve $ hg commit -m "precious commit message" $ hg serve -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log $ cat hg.pid >> $DAEMON_PIDS $ cd .. $ hg clone http://localhost:$HGPORT u requesting all changes adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 1 files (+1 heads) updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd u $ hg id default 068774709090 now rollback and observe that 'hg serve' reloads the repository and presents the correct tip changeset: $ hg -R ../t rollback repository tip rolled back to revision 1 (undo commit) working directory now based on revision 0 $ hg id default 791dd2169706 #endif update to older changeset and then refuse rollback, because that would lose data (issue2998) $ cd ../t $ hg -q update $ rm `hg status -un` $ template='{rev}:{node|short} [{branch}] {desc|firstline}\n' $ echo 'valuable new file' > b $ echo 'valuable modification' >> a $ hg commit -A -m'a valuable change' adding b $ hg update 0 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg rollback abort: rollback of last commit while not checked out may lose data (use -f to force) [255] $ hg tip -q 2:4d9cd3795eea $ hg rollback -f repository tip rolled back to revision 1 (undo commit) $ hg status $ hg log --removed b # yep, it's gone same again, but emulate an old client that doesn't write undo.desc $ hg -q update $ echo 'valuable modification redux' >> a $ hg commit -m'a valuable change redux' $ rm .hg/undo.desc $ hg update 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg rollback rolling back unknown transaction $ cat a a corrupt journal test $ echo "foo" > .hg/store/journal $ hg recover rolling back interrupted transaction couldn't read journal entry 'foo\n'! checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 2 changesets, 2 total revisions rollback disabled by config $ cat >> $HGRCPATH <<EOF > [ui] > rollback = false > EOF $ echo narf >> pinky-sayings.txt $ hg add pinky-sayings.txt $ hg ci -m 'First one.' $ hg rollback abort: rollback is disabled because it is unsafe (see `hg help -v rollback` for information) [255]