localrepo: experimental support for non-zlib revlog compression
The final part of integrating the compression manager APIs into
revlog storage is the plumbing for repositories to advertise they
are using non-zlib storage and for revlogs to instantiate a non-zlib
compression engine.
The main intent of the compression manager work was to zstd all
of the things. Adding zstd to revlogs has proved to be more involved
than other places because revlogs are... special. Very small inputs
and the use of delta chains (which are themselves a form of
compression) are a completely different use case from streaming
compression, which bundles and the wire protocol employ. I've
conducted numerous experiments with zstd in revlogs and have yet
to formalize compression settings and a storage architecture that
I'm confident I won't regret later. In other words, I'm not yet
ready to commit to a new mechanism for using zstd - or any other
compression format - in revlogs.
That being said, having some support for zstd (and other compression
formats) in revlogs in core is beneficial. It can allow others to
conduct experiments.
This patch introduces *highly experimental* support for non-zlib
compression formats in revlogs. Introduced is a config option to
control which compression engine to use. Also introduced is a namespace
of "exp-compression-*" requirements to denote support for non-zlib
compression in revlogs. I've prefixed the namespace with "exp-"
(short for "experimental") because I'm not confident of the
requirements "schema" and in no way want to give the illusion of
supporting these requirements in the future. I fully intend to drop
support for these requirements once we figure out what we're doing
with zstd in revlogs.
A good portion of the patch is teaching the requirements system
about registered compression engines and passing the requested
compression engine as an opener option so revlogs can instantiate
the proper compression engine for new operations.
That's a verbose way of saying "we can now use zstd in revlogs!"
On an `hg pull` conversion of the mozilla-unified repo with no extra
redelta settings (like aggressivemergedeltas), we can see the impact
of zstd vs zlib in revlogs:
$ hg perfrevlogchunks -c
! chunk
! wall 2.032052 comb 2.040000 user 1.990000 sys 0.050000 (best of 5)
! wall 1.866360 comb 1.860000 user 1.820000 sys 0.040000 (best of 6)
! chunk batch
! wall 1.877261 comb 1.870000 user 1.860000 sys 0.010000 (best of 6)
! wall 1.705410 comb 1.710000 user 1.690000 sys 0.020000 (best of 6)
$ hg perfrevlogchunks -m
! chunk
! wall 2.721427 comb 2.720000 user 2.640000 sys 0.080000 (best of 4)
! wall 2.035076 comb 2.030000 user 1.950000 sys 0.080000 (best of 5)
! chunk batch
! wall 2.614561 comb 2.620000 user 2.580000 sys 0.040000 (best of 4)
! wall 1.910252 comb 1.910000 user 1.880000 sys 0.030000 (best of 6)
$ hg perfrevlog -c -d 1
! wall 4.812885 comb 4.820000 user 4.800000 sys 0.020000 (best of 3)
! wall 4.699621 comb 4.710000 user 4.700000 sys 0.010000 (best of 3)
$ hg perfrevlog -m -d 1000
! wall 34.252800 comb 34.250000 user 33.730000 sys 0.520000 (best of 3)
! wall 24.094999 comb 24.090000 user 23.320000 sys 0.770000 (best of 3)
Only modest wins for the changelog. But manifest reading is
significantly faster. What's going on?
One reason might be data volume. zstd decompresses faster. So given
more bytes, it will put more distance between it and zlib.
Another reason is size. In the current design, zstd revlogs are
*larger*:
debugcreatestreamclonebundle (size in bytes)
zlib: 1,638,852,492
zstd: 1,680,601,332
I haven't investigated this fully, but I reckon a significant cause of
larger revlogs is that the zstd frame/header has more bytes than
zlib's. For very small inputs or data that doesn't compress well, we'll
tend to store more uncompressed chunks than with zlib (because the
compressed size isn't smaller than original). This will make revlog
reading faster because it is doing less decompression.
Moving on to bundle performance:
$ hg bundle -a -t none-v2 (total CPU time)
zlib: 102.79s
zstd: 97.75s
So, marginal CPU decrease for reading all chunks in all revlogs
(this is somewhat disappointing).
$ hg bundle -a -t <engine>-v2 (total CPU time)
zlib: 191.59s
zstd: 115.36s
This last test effectively measures the difference between zlib->zlib
and zstd->zstd for revlogs to bundle. This is a rough approximation of
what a server does during `hg clone`.
There are some promising results for zstd. But not enough for me to
feel comfortable advertising it to users. We'll get there...
$ hg init t
$ cd t
$ echo import > port
$ hg add port
$ hg commit -m 0 -u spam -d '0 0'
$ echo export >> port
$ hg commit -m 1 -u eggs -d '1 0'
$ echo export > port
$ echo vaportight >> port
$ echo 'import/export' >> port
$ hg commit -m 2 -u spam -d '2 0'
$ echo 'import/export' >> port
$ hg commit -m 3 -u eggs -d '3 0'
$ head -n 3 port > port1
$ mv port1 port
$ hg commit -m 4 -u spam -d '4 0'
pattern error
$ hg grep '**test**'
grep: invalid match pattern: nothing to repeat
[1]
simple
$ hg grep '.*'
port:4:export
port:4:vaportight
port:4:import/export
$ hg grep port port
port:4:export
port:4:vaportight
port:4:import/export
simple with color
$ hg --config extensions.color= grep --config color.mode=ansi \
> --color=always port port
\x1b[0;35mport\x1b[0m\x1b[0;36m:\x1b[0m\x1b[0;32m4\x1b[0m\x1b[0;36m:\x1b[0mex\x1b[0;31;1mport\x1b[0m (esc)
\x1b[0;35mport\x1b[0m\x1b[0;36m:\x1b[0m\x1b[0;32m4\x1b[0m\x1b[0;36m:\x1b[0mva\x1b[0;31;1mport\x1b[0might (esc)
\x1b[0;35mport\x1b[0m\x1b[0;36m:\x1b[0m\x1b[0;32m4\x1b[0m\x1b[0;36m:\x1b[0mim\x1b[0;31;1mport\x1b[0m/ex\x1b[0;31;1mport\x1b[0m (esc)
simple templated
$ hg grep port \
> -T '{file}:{rev}:{node|short}:{texts % "{if(matched, text|upper, text)}"}\n'
port:4:914fa752cdea:exPORT
port:4:914fa752cdea:vaPORTight
port:4:914fa752cdea:imPORT/exPORT
simple JSON (no "change" field)
$ hg grep -Tjson port
[
{
"date": [4.0, 0],
"file": "port",
"line_number": 1,
"node": "914fa752cdea87777ac1a8d5c858b0c736218f6c",
"rev": 4,
"texts": [{"matched": false, "text": "ex"}, {"matched": true, "text": "port"}],
"user": "spam"
},
{
"date": [4.0, 0],
"file": "port",
"line_number": 2,
"node": "914fa752cdea87777ac1a8d5c858b0c736218f6c",
"rev": 4,
"texts": [{"matched": false, "text": "va"}, {"matched": true, "text": "port"}, {"matched": false, "text": "ight"}],
"user": "spam"
},
{
"date": [4.0, 0],
"file": "port",
"line_number": 3,
"node": "914fa752cdea87777ac1a8d5c858b0c736218f6c",
"rev": 4,
"texts": [{"matched": false, "text": "im"}, {"matched": true, "text": "port"}, {"matched": false, "text": "/ex"}, {"matched": true, "text": "port"}],
"user": "spam"
}
]
simple JSON without matching lines
$ hg grep -Tjson -l port
[
{
"date": [4.0, 0],
"file": "port",
"line_number": 1,
"node": "914fa752cdea87777ac1a8d5c858b0c736218f6c",
"rev": 4,
"user": "spam"
}
]
all
$ hg grep --traceback --all -nu port port
port:4:4:-:spam:import/export
port:3:4:+:eggs:import/export
port:2:1:-:spam:import
port:2:2:-:spam:export
port:2:1:+:spam:export
port:2:2:+:spam:vaportight
port:2:3:+:spam:import/export
port:1:2:+:eggs:export
port:0:1:+:spam:import
all JSON
$ hg grep --all -Tjson port port
[
{
"change": "-",
"date": [4.0, 0],
"file": "port",
"line_number": 4,
"node": "914fa752cdea87777ac1a8d5c858b0c736218f6c",
"rev": 4,
"texts": [{"matched": false, "text": "im"}, {"matched": true, "text": "port"}, {"matched": false, "text": "/ex"}, {"matched": true, "text": "port"}],
"user": "spam"
},
{
"change": "+",
"date": [3.0, 0],
"file": "port",
"line_number": 4,
"node": "95040cfd017d658c536071c6290230a613c4c2a6",
"rev": 3,
"texts": [{"matched": false, "text": "im"}, {"matched": true, "text": "port"}, {"matched": false, "text": "/ex"}, {"matched": true, "text": "port"}],
"user": "eggs"
},
{
"change": "-",
"date": [2.0, 0],
"file": "port",
"line_number": 1,
"node": "3b325e3481a1f07435d81dfdbfa434d9a0245b47",
"rev": 2,
"texts": [{"matched": false, "text": "im"}, {"matched": true, "text": "port"}],
"user": "spam"
},
{
"change": "-",
"date": [2.0, 0],
"file": "port",
"line_number": 2,
"node": "3b325e3481a1f07435d81dfdbfa434d9a0245b47",
"rev": 2,
"texts": [{"matched": false, "text": "ex"}, {"matched": true, "text": "port"}],
"user": "spam"
},
{
"change": "+",
"date": [2.0, 0],
"file": "port",
"line_number": 1,
"node": "3b325e3481a1f07435d81dfdbfa434d9a0245b47",
"rev": 2,
"texts": [{"matched": false, "text": "ex"}, {"matched": true, "text": "port"}],
"user": "spam"
},
{
"change": "+",
"date": [2.0, 0],
"file": "port",
"line_number": 2,
"node": "3b325e3481a1f07435d81dfdbfa434d9a0245b47",
"rev": 2,
"texts": [{"matched": false, "text": "va"}, {"matched": true, "text": "port"}, {"matched": false, "text": "ight"}],
"user": "spam"
},
{
"change": "+",
"date": [2.0, 0],
"file": "port",
"line_number": 3,
"node": "3b325e3481a1f07435d81dfdbfa434d9a0245b47",
"rev": 2,
"texts": [{"matched": false, "text": "im"}, {"matched": true, "text": "port"}, {"matched": false, "text": "/ex"}, {"matched": true, "text": "port"}],
"user": "spam"
},
{
"change": "+",
"date": [1.0, 0],
"file": "port",
"line_number": 2,
"node": "8b20f75c158513ff5ac80bd0e5219bfb6f0eb587",
"rev": 1,
"texts": [{"matched": false, "text": "ex"}, {"matched": true, "text": "port"}],
"user": "eggs"
},
{
"change": "+",
"date": [0.0, 0],
"file": "port",
"line_number": 1,
"node": "f31323c9217050ba245ee8b537c713ec2e8ab226",
"rev": 0,
"texts": [{"matched": false, "text": "im"}, {"matched": true, "text": "port"}],
"user": "spam"
}
]
other
$ hg grep -l port port
port:4
$ hg grep import port
port:4:import/export
$ hg cp port port2
$ hg commit -m 4 -u spam -d '5 0'
follow
$ hg grep --traceback -f 'import\n\Z' port2
port:0:import
$ echo deport >> port2
$ hg commit -m 5 -u eggs -d '6 0'
$ hg grep -f --all -nu port port2
port2:6:4:+:eggs:deport
port:4:4:-:spam:import/export
port:3:4:+:eggs:import/export
port:2:1:-:spam:import
port:2:2:-:spam:export
port:2:1:+:spam:export
port:2:2:+:spam:vaportight
port:2:3:+:spam:import/export
port:1:2:+:eggs:export
port:0:1:+:spam:import
$ hg up -q null
$ hg grep -f port
[1]
$ cd ..
$ hg init t2
$ cd t2
$ hg grep foobar foo
[1]
$ hg grep foobar
[1]
$ echo blue >> color
$ echo black >> color
$ hg add color
$ hg ci -m 0
$ echo orange >> color
$ hg ci -m 1
$ echo black > color
$ hg ci -m 2
$ echo orange >> color
$ echo blue >> color
$ hg ci -m 3
$ hg grep orange
color:3:orange
$ hg grep --all orange
color:3:+:orange
color:2:-:orange
color:1:+:orange
test substring match: '^' should only match at the beginning
$ hg grep '^.' --config extensions.color= --color debug
[grep.filename|color][grep.sep|:][grep.rev|3][grep.sep|:][grep.match|b]lack
[grep.filename|color][grep.sep|:][grep.rev|3][grep.sep|:][grep.match|o]range
[grep.filename|color][grep.sep|:][grep.rev|3][grep.sep|:][grep.match|b]lue
match in last "line" without newline
$ $PYTHON -c 'fp = open("noeol", "wb"); fp.write("no infinite loop"); fp.close();'
$ hg ci -Amnoeol
adding noeol
$ hg grep loop
noeol:4:no infinite loop
$ cd ..
Issue685: traceback in grep -r after rename
Got a traceback when using grep on a single
revision with renamed files.
$ hg init issue685
$ cd issue685
$ echo octarine > color
$ hg ci -Amcolor
adding color
$ hg rename color colour
$ hg ci -Am rename
$ hg grep octarine
colour:1:octarine
color:0:octarine
Used to crash here
$ hg grep -r 1 octarine
colour:1:octarine
$ cd ..
Issue337: test that grep follows parent-child relationships instead
of just using revision numbers.
$ hg init issue337
$ cd issue337
$ echo white > color
$ hg commit -A -m "0 white"
adding color
$ echo red > color
$ hg commit -A -m "1 red"
$ hg update 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo black > color
$ hg commit -A -m "2 black"
created new head
$ hg update --clean 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo blue > color
$ hg commit -A -m "3 blue"
$ hg grep --all red
color:3:-:red
color:1:+:red
$ cd ..
$ hg init a
$ cd a
$ cp "$TESTDIR/binfile.bin" .
$ hg add binfile.bin
$ hg ci -m 'add binfile.bin'
$ hg grep "MaCam" --all
binfile.bin:0:+: Binary file matches
$ cd ..