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
$ mkdir d1 d1/d11 d2
$ echo d1/a > d1/a
$ echo d1/ba > d1/ba
$ echo d1/a1 > d1/d11/a1
$ echo d1/b > d1/b
$ echo d2/b > d2/b
$ hg add d1/a d1/b d1/ba d1/d11/a1 d2/b
$ hg commit -m "1"
rename a single file
$ hg rename d1/d11/a1 d2/c
$ hg --config ui.portablefilenames=abort rename d1/a d1/con.xml
abort: filename contains 'con', which is reserved on Windows: 'd1/con.xml'
[255]
$ hg sum
parent: 0:9b4b6e7b2c26 tip
1
branch: default
commit: 1 renamed
update: (current)
phases: 1 draft
$ hg status -C
A d2/c
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/c
rename a single file using absolute paths
$ hg rename `pwd`/d1/d11/a1 `pwd`/d2/c
$ hg status -C
A d2/c
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/c
rename --after a single file
$ mv d1/d11/a1 d2/c
$ hg rename --after d1/d11/a1 d2/c
$ hg status -C
A d2/c
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/c
rename --after a single file when src and tgt already tracked
$ mv d1/d11/a1 d2/c
$ hg addrem -s 0
removing d1/d11/a1
adding d2/c
$ hg rename --after d1/d11/a1 d2/c
$ hg status -C
A d2/c
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/c
rename --after a single file to a nonexistent target filename
$ hg rename --after d1/a dummy
d1/a: not recording move - dummy does not exist (glob)
move a single file to an existing directory
$ hg rename d1/d11/a1 d2
$ hg status -C
A d2/a1
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/a1
move --after a single file to an existing directory
$ mv d1/d11/a1 d2
$ hg rename --after d1/d11/a1 d2
$ hg status -C
A d2/a1
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/a1
rename a file using a relative path
$ (cd d1/d11; hg rename ../../d2/b e)
$ hg status -C
A d1/d11/e
d2/b
R d2/b
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/d11/e
rename --after a file using a relative path
$ (cd d1/d11; mv ../../d2/b e; hg rename --after ../../d2/b e)
$ hg status -C
A d1/d11/e
d2/b
R d2/b
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/d11/e
rename directory d1 as d3
$ hg rename d1/ d3
moving d1/a to d3/a (glob)
moving d1/b to d3/b (glob)
moving d1/ba to d3/ba (glob)
moving d1/d11/a1 to d3/d11/a1 (glob)
$ hg status -C
A d3/a
d1/a
A d3/b
d1/b
A d3/ba
d1/ba
A d3/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
rename --after directory d1 as d3
$ mv d1 d3
$ hg rename --after d1 d3
moving d1/a to d3/a (glob)
moving d1/b to d3/b (glob)
moving d1/ba to d3/ba (glob)
moving d1/d11/a1 to d3/d11/a1 (glob)
$ hg status -C
A d3/a
d1/a
A d3/b
d1/b
A d3/ba
d1/ba
A d3/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
move a directory using a relative path
$ (cd d2; mkdir d3; hg rename ../d1/d11 d3)
moving ../d1/d11/a1 to d3/d11/a1 (glob)
$ hg status -C
A d2/d3/d11/a1
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d2/d3
move --after a directory using a relative path
$ (cd d2; mkdir d3; mv ../d1/d11 d3; hg rename --after ../d1/d11 d3)
moving ../d1/d11/a1 to d3/d11/a1 (glob)
$ hg status -C
A d2/d3/d11/a1
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d2/d3
move directory d1/d11 to an existing directory d2 (removes empty d1)
$ hg rename d1/d11/ d2
moving d1/d11/a1 to d2/d11/a1 (glob)
$ hg status -C
A d2/d11/a1
d1/d11/a1
R d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d2/d11
move directories d1 and d2 to a new directory d3
$ mkdir d3
$ hg rename d1 d2 d3
moving d1/a to d3/d1/a (glob)
moving d1/b to d3/d1/b (glob)
moving d1/ba to d3/d1/ba (glob)
moving d1/d11/a1 to d3/d1/d11/a1 (glob)
moving d2/b to d3/d2/b (glob)
$ hg status -C
A d3/d1/a
d1/a
A d3/d1/b
d1/b
A d3/d1/ba
d1/ba
A d3/d1/d11/a1
d1/d11/a1
A d3/d2/b
d2/b
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
R d2/b
$ hg update -C
5 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
move --after directories d1 and d2 to a new directory d3
$ mkdir d3
$ mv d1 d2 d3
$ hg rename --after d1 d2 d3
moving d1/a to d3/d1/a (glob)
moving d1/b to d3/d1/b (glob)
moving d1/ba to d3/d1/ba (glob)
moving d1/d11/a1 to d3/d1/d11/a1 (glob)
moving d2/b to d3/d2/b (glob)
$ hg status -C
A d3/d1/a
d1/a
A d3/d1/b
d1/b
A d3/d1/ba
d1/ba
A d3/d1/d11/a1
d1/d11/a1
A d3/d2/b
d2/b
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
R d2/b
$ hg update -C
5 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
move everything under directory d1 to existing directory d2, do not
overwrite existing files (d2/b)
$ hg rename d1/* d2
d2/b: not overwriting - file already committed
(hg rename --force to replace the file by recording a rename)
moving d1/d11/a1 to d2/d11/a1 (glob)
$ hg status -C
A d2/a
d1/a
A d2/ba
d1/ba
A d2/d11/a1
d1/d11/a1
R d1/a
R d1/ba
R d1/d11/a1
$ diff -u d1/b d2/b
--- d1/b * (glob)
+++ d2/b * (glob)
@@ * (glob)
-d1/b
+d2/b
[1]
$ hg update -C
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d2/a d2/ba d2/d11/a1
attempt to move one file into a non-existent directory
$ hg rename d1/a dx/
abort: destination dx/ is not a directory
[255]
$ hg status -C
$ hg update -C
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
attempt to move potentially more than one file into a non-existent directory
$ hg rename 'glob:d1/**' dx
abort: with multiple sources, destination must be an existing directory
[255]
move every file under d1 to d2/d21 (glob)
$ mkdir d2/d21
$ hg rename 'glob:d1/**' d2/d21
moving d1/a to d2/d21/a (glob)
moving d1/b to d2/d21/b (glob)
moving d1/ba to d2/d21/ba (glob)
moving d1/d11/a1 to d2/d21/a1 (glob)
$ hg status -C
A d2/d21/a
d1/a
A d2/d21/a1
d1/d11/a1
A d2/d21/b
d1/b
A d2/d21/ba
d1/ba
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d2/d21
move --after some files under d1 to d2/d21 (glob)
$ mkdir d2/d21
$ mv d1/a d1/d11/a1 d2/d21
$ hg rename --after 'glob:d1/**' d2/d21
moving d1/a to d2/d21/a (glob)
d1/b: not recording move - d2/d21/b does not exist (glob)
d1/ba: not recording move - d2/d21/ba does not exist (glob)
moving d1/d11/a1 to d2/d21/a1 (glob)
$ hg status -C
A d2/d21/a
d1/a
A d2/d21/a1
d1/d11/a1
R d1/a
R d1/d11/a1
$ hg update -C
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d2/d21
move every file under d1 starting with an 'a' to d2/d21 (regexp)
$ mkdir d2/d21
$ hg rename 're:d1/([^a][^/]*/)*a.*' d2/d21
moving d1/a to d2/d21/a (glob)
moving d1/d11/a1 to d2/d21/a1 (glob)
$ hg status -C
A d2/d21/a
d1/a
A d2/d21/a1
d1/d11/a1
R d1/a
R d1/d11/a1
$ hg update -C
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d2/d21
attempt to overwrite an existing file
$ echo "ca" > d1/ca
$ hg rename d1/ba d1/ca
d1/ca: not overwriting - file exists
(hg rename --after to record the rename)
$ hg status -C
? d1/ca
$ hg update -C
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
forced overwrite of an existing file
$ echo "ca" > d1/ca
$ hg rename --force d1/ba d1/ca
$ hg status -C
A d1/ca
d1/ba
R d1/ba
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/ca
attempt to overwrite an existing broken symlink
#if symlink
$ ln -s ba d1/ca
$ hg rename --traceback d1/ba d1/ca
d1/ca: not overwriting - file exists
(hg rename --after to record the rename)
$ hg status -C
? d1/ca
$ hg update -C
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/ca
replace a symlink with a file
$ ln -s ba d1/ca
$ hg rename --force d1/ba d1/ca
$ hg status -C
A d1/ca
d1/ba
R d1/ba
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/ca
#endif
do not copy more than one source file to the same destination file
$ mkdir d3
$ hg rename d1/* d2/* d3
moving d1/d11/a1 to d3/d11/a1 (glob)
d3/b: not overwriting - d2/b collides with d1/b
$ hg status -C
A d3/a
d1/a
A d3/b
d1/b
A d3/ba
d1/ba
A d3/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
move a whole subtree with "hg rename ."
$ mkdir d3
$ (cd d1; hg rename . ../d3)
moving a to ../d3/d1/a
moving b to ../d3/d1/b
moving ba to ../d3/d1/ba
moving d11/a1 to ../d3/d1/d11/a1 (glob)
$ hg status -C
A d3/d1/a
d1/a
A d3/d1/b
d1/b
A d3/d1/ba
d1/ba
A d3/d1/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
move a whole subtree with "hg rename --after ."
$ mkdir d3
$ mv d1/* d3
$ (cd d1; hg rename --after . ../d3)
moving a to ../d3/a
moving b to ../d3/b
moving ba to ../d3/ba
moving d11/a1 to ../d3/d11/a1 (glob)
$ hg status -C
A d3/a
d1/a
A d3/b
d1/b
A d3/ba
d1/ba
A d3/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
move the parent tree with "hg rename .."
$ (cd d1/d11; hg rename .. ../../d3)
moving ../a to ../../d3/a (glob)
moving ../b to ../../d3/b (glob)
moving ../ba to ../../d3/ba (glob)
moving a1 to ../../d3/d11/a1
$ hg status -C
A d3/a
d1/a
A d3/b
d1/b
A d3/ba
d1/ba
A d3/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
skip removed files
$ hg remove d1/b
$ hg rename d1 d3
moving d1/a to d3/a (glob)
moving d1/ba to d3/ba (glob)
moving d1/d11/a1 to d3/d11/a1 (glob)
$ hg status -C
A d3/a
d1/a
A d3/ba
d1/ba
A d3/d11/a1
d1/d11/a1
R d1/a
R d1/b
R d1/ba
R d1/d11/a1
$ hg update -C
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm -rf d3
transitive rename
$ hg rename d1/b d1/bb
$ hg rename d1/bb d1/bc
$ hg status -C
A d1/bc
d1/b
R d1/b
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/bc
transitive rename --after
$ hg rename d1/b d1/bb
$ mv d1/bb d1/bc
$ hg rename --after d1/bb d1/bc
$ hg status -C
A d1/bc
d1/b
R d1/b
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/bc
$ echo "# idempotent renames (d1/b -> d1/bb followed by d1/bb -> d1/b)"
# idempotent renames (d1/b -> d1/bb followed by d1/bb -> d1/b)
$ hg rename d1/b d1/bb
$ echo "some stuff added to d1/bb" >> d1/bb
$ hg rename d1/bb d1/b
$ hg status -C
M d1/b
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
overwriting with renames (issue1959)
$ hg rename d1/a d1/c
$ hg rename d1/b d1/a
$ hg status -C
M d1/a
d1/b
A d1/c
d1/a
R d1/b
$ hg diff --git
diff --git a/d1/a b/d1/a
--- a/d1/a
+++ b/d1/a
@@ -1,1 +1,1 @@
-d1/a
+d1/b
diff --git a/d1/b b/d1/b
deleted file mode 100644
--- a/d1/b
+++ /dev/null
@@ -1,1 +0,0 @@
-d1/b
diff --git a/d1/a b/d1/c
copy from d1/a
copy to d1/c
$ hg update -C
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm d1/c # The file was marked as added, so 'hg update' action was 'forget'
check illegal path components
$ hg rename d1/d11/a1 .hg/foo
abort: path contains illegal component: .hg/foo (glob)
[255]
$ hg status -C
$ hg rename d1/d11/a1 ../foo
abort: ../foo not under root '$TESTTMP'
[255]
$ hg status -C
$ mv d1/d11/a1 .hg/foo
$ hg rename --after d1/d11/a1 .hg/foo
abort: path contains illegal component: .hg/foo (glob)
[255]
$ hg status -C
! d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm .hg/foo
$ hg rename d1/d11/a1 .hg
abort: path contains illegal component: .hg/a1 (glob)
[255]
$ hg --config extensions.largefiles= rename d1/d11/a1 .hg
abort: path contains illegal component: .hg/a1 (glob)
[255]
$ hg status -C
$ hg rename d1/d11/a1 ..
abort: ../a1 not under root '$TESTTMP' (glob)
[255]
$ hg --config extensions.largefiles= rename d1/d11/a1 ..
abort: ../a1 not under root '$TESTTMP' (glob)
[255]
$ hg status -C
$ mv d1/d11/a1 .hg
$ hg rename --after d1/d11/a1 .hg
abort: path contains illegal component: .hg/a1 (glob)
[255]
$ hg status -C
! d1/d11/a1
$ hg update -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ rm .hg/a1
$ (cd d1/d11; hg rename ../../d2/b ../../.hg/foo)
abort: path contains illegal component: .hg/foo (glob)
[255]
$ hg status -C
$ (cd d1/d11; hg rename ../../d2/b ../../../foo)
abort: ../../../foo not under root '$TESTTMP'
[255]
$ hg status -C