view tests/test-phases.t @ 30155:b7a966ce89ed

changelog: disable delta chains

This patch disables delta chains on changelogs. After this patch, new
entries on changelogs - including existing changelogs - will be stored
as the fulltext of that data (likely compressed). No delta computation
will be performed.

An overview of delta chains and data justifying this change follows.

Revlogs try to store entries as a delta against a previous entry (either
a parent revision in the case of generaldelta or the previous physical
revision when not using generaldelta). Most of the time this is the
correct thing to do: it frequently results in less CPU usage and smaller
storage.

Delta chains are most effective when the base revision being deltad
against is similar to the current data. This tends to occur naturally
for manifests and file data, since only small parts of each tend to
change with each revision. Changelogs, however, are a different story.

Changelog entries represent changesets/commits. And unless commits in a
repository are homogonous (same author, changing same files, similar
commit messages, etc), a delta from one entry to the next tends to be
relatively large compared to the size of the entry. This means that
delta chains tend to be short. How short? Here is the full vs delta
revision breakdown on some real world repos:

Repo             % Full    % Delta   Max Length
hg                45.8       54.2        6
mozilla-central   42.4       57.6        8
mozilla-unified   42.5       57.5       17
pypy              46.1       53.9        6
python-zstandard  46.1       53.9        3

(I threw in python-zstandard as an example of a repo that is homogonous.
It contains a small Python project with changes all from the same
author.)

Contrast this with the manifest revlog for these repos, where 99+% of
revisions are deltas and delta chains run into the thousands.

So delta chains aren't as useful on changelogs. But even a short delta
chain may provide benefits. Let's measure that.

Delta chains may require less CPU to read revisions if the CPU time
spent reading smaller deltas is less than the CPU time used to
decompress larger individual entries. We can measure this via
`hg perfrevlog -c -d 1` to iterate a revlog to resolve each revision's
fulltext. Here are the results of that command on a repo using delta
chains in its changelog and on a repo without delta chains:

hg (forward)
! wall 0.407008 comb 0.410000 user 0.410000 sys 0.000000 (best of 25)
! wall 0.390061 comb 0.390000 user 0.390000 sys 0.000000 (best of 26)

hg (reverse)
! wall 0.515221 comb 0.520000 user 0.520000 sys 0.000000 (best of 19)
! wall 0.400018 comb 0.400000 user 0.390000 sys 0.010000 (best of 25)

mozilla-central (forward)
! wall 4.508296 comb 4.490000 user 4.490000 sys 0.000000 (best of 3)
! wall 4.370222 comb 4.370000 user 4.350000 sys 0.020000 (best of 3)

mozilla-central (reverse)
! wall 5.758995 comb 5.760000 user 5.720000 sys 0.040000 (best of 3)
! wall 4.346503 comb 4.340000 user 4.320000 sys 0.020000 (best of 3)

mozilla-unified (forward)
! wall 4.957088 comb 4.950000 user 4.940000 sys 0.010000 (best of 3)
! wall 4.660528 comb 4.650000 user 4.630000 sys 0.020000 (best of 3)

mozilla-unified (reverse)
! wall 6.119827 comb 6.110000 user 6.090000 sys 0.020000 (best of 3)
! wall 4.675136 comb 4.670000 user 4.670000 sys 0.000000 (best of 3)

pypy (forward)
! wall 1.231122 comb 1.240000 user 1.230000 sys 0.010000 (best of 8)
! wall 1.164896 comb 1.160000 user 1.160000 sys 0.000000 (best of 9)

pypy (reverse)
! wall 1.467049 comb 1.460000 user 1.460000 sys 0.000000 (best of 7)
! wall 1.160200 comb 1.170000 user 1.160000 sys 0.010000 (best of 9)

The data clearly shows that it takes less wall and CPU time to resolve
revisions when there are no delta chains in the changelogs, regardless
of the direction of traversal. Furthermore, not using a delta chain
means that fulltext resolution in reverse is as fast as iterating
forward. So not using delta chains on the changelog is a clear CPU win
for reading operations.

An example of a user-visible operation showing this speed-up is revset
evaluation. Here are results for
`hg perfrevset 'author(gps) or author(mpm)'`:

hg
! wall 1.655506 comb 1.660000 user 1.650000 sys 0.010000 (best of 6)
! wall 1.612723 comb 1.610000 user 1.600000 sys 0.010000 (best of 7)

mozilla-central
! wall 17.629826 comb 17.640000 user 17.600000 sys 0.040000 (best of 3)
! wall 17.311033 comb 17.300000 user 17.260000 sys 0.040000 (best of 3)

What about 00changelog.i size?

Repo                Delta Chains     No Delta Chains
hg                    7,033,250         6,976,771
mozilla-central      82,978,748        81,574,623
mozilla-unified      88,112,349        86,702,162
pypy                 20,740,699        20,659,741

The data shows that removing delta chains from the changelog makes the
changelog smaller.

Delta chains are also used during changegroup generation. This
operation essentially converts a series of revisions to one large
delta chain. And changegroup generation is smart: if the delta in
the revlog matches what the changegroup is emitting, it will reuse
the delta instead of recalculating it. We can measure the impact
removing changelog delta chains has on changegroup generation via
`hg perfchangegroupchangelog`:

hg
! wall 1.589245 comb 1.590000 user 1.590000 sys 0.000000 (best of 7)
! wall 1.788060 comb 1.790000 user 1.790000 sys 0.000000 (best of 6)

mozilla-central
! wall 17.382585 comb 17.380000 user 17.340000 sys 0.040000 (best of 3)
! wall 20.161357 comb 20.160000 user 20.120000 sys 0.040000 (best of 3)

mozilla-unified
! wall 18.722839 comb 18.720000 user 18.680000 sys 0.040000 (best of 3)
! wall 21.168075 comb 21.170000 user 21.130000 sys 0.040000 (best of 3)

pypy
! wall 4.828317 comb 4.830000 user 4.820000 sys 0.010000 (best of 3)
! wall 5.415455 comb 5.420000 user 5.410000 sys 0.010000 (best of 3)

The data shows eliminating delta chains makes the changelog part of
changegroup generation slower. This is expected since we now have to
compute deltas for revisions where we could recycle the delta before.

It is worth putting this regression into context of overall changegroup
times. Here is the rough total CPU time spent in changegroup generation
for various repos while using delta chains on the changelog:

Repo              CPU Time (s)    CPU Time w/ compression
hg                  4.50              7.05
mozilla-central   111.1             222.0
pypy               28.68             75.5

Before compression, removing delta chains from the changegroup adds
~4.4% overhead to hg changegroup generation, 1.3% to mozilla-central,
and 2.0% to pypy. When you factor in zlib compression, these percentages
are roughly divided by 2.

While the increased CPU usage for changegroup generation is unfortunate,
I think it is acceptable because the percentage is small, server
operators (those likely impacted most by this) have other mechanisms
to mitigate CPU consumption (namely reducing zlib compression level and
pre-generated clone bundles), and because there is room to optimize this
in the future. For example, we could use the nullid as the base revision,
effectively encoding the full revision for each entry in the changegroup.
When doing this, `hg perfchangegroupchangelog` nearly halves:

mozilla-unified
! wall 21.168075 comb 21.170000 user 21.130000 sys 0.040000 (best of 3)
! wall 11.196461 comb 11.200000 user 11.190000 sys 0.010000 (best of 3)

This looks very promising as a future optimization opportunity.

It's worth that the changes in test-acl.t to the changegroup part size.
This is because revision 6 in the changegroup had a delta chain of
length 2 before and after this patch the base revision is nullrev.
When the base revision is nullrev, cg2packer.deltaparent() hardcodes
the *previous* revision from the changegroup as the delta parent.
This caused the delta in the changegroup to switch base revisions,
the delta to change, and the size to change accordingly. While the
size increased in this case, I think sizes will remain the same
on average, as the delta base for changelog revisions doesn't matter
too much (as this patch shows). So, I don't consider this a regression.

  $ hglog() { hg log --template "{rev} {phaseidx} {desc}\n" $*; }
  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    message="$1"
  >    shift
  >    hg ci -m "$message" $*
  > }

  $ hg init initialrepo
  $ cd initialrepo

Cannot change null revision phase

  $ hg phase --force --secret null
  abort: cannot change null revision phase
  [255]
  $ hg phase null
  -1: public

  $ mkcommit A

New commit are draft by default

  $ hglog
  0 1 A

Following commit are draft too

  $ mkcommit B

  $ hglog
  1 1 B
  0 1 A

Draft commit are properly created over public one:

  $ hg phase --public .
  $ hg phase
  1: public
  $ hglog
  1 0 B
  0 0 A

  $ mkcommit C
  $ mkcommit D

  $ hglog
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Test creating changeset as secret

  $ mkcommit E --config phases.new-commit='secret'
  $ hglog
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Test the secret property is inherited

  $ mkcommit H
  $ hglog
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Even on merge

  $ hg up -q 1
  $ mkcommit "B'"
  created new head
  $ hglog
  6 1 B'
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A
  $ hg merge 4 # E
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg phase
  6: draft
  4: secret
  $ hg ci -m "merge B' and E"
  $ hglog
  7 2 merge B' and E
  6 1 B'
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Test secret changeset are not pushed

  $ hg init ../push-dest
  $ cat > ../push-dest/.hg/hgrc << EOF
  > [phases]
  > publish=False
  > EOF
  $ hg outgoing ../push-dest --template='{rev} {phase} {desc|firstline}\n'
  comparing with ../push-dest
  searching for changes
  0 public A
  1 public B
  2 draft C
  3 draft D
  6 draft B'
  $ hg outgoing -r 'branch(default)' ../push-dest --template='{rev} {phase} {desc|firstline}\n'
  comparing with ../push-dest
  searching for changes
  0 public A
  1 public B
  2 draft C
  3 draft D
  6 draft B'

  $ hg push ../push-dest -f # force because we push multiple heads
  pushing to ../push-dest
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 5 files (+1 heads)
  $ hglog
  7 2 merge B' and E
  6 1 B'
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A
  $ cd ../push-dest
  $ hglog
  4 1 B'
  3 1 D
  2 1 C
  1 0 B
  0 0 A

(Issue3303)
Check that remote secret changeset are ignore when checking creation of remote heads

We add a secret head into the push destination. This secret head shadows a
visible shared between the initial repo and the push destination.

  $ hg up -q 4 # B'
  $ mkcommit Z --config phases.new-commit=secret
  $ hg phase .
  5: secret

We now try to push a new public changeset that descend from the common public
head shadowed by the remote secret head.

  $ cd ../initialrepo
  $ hg up -q 6 #B'
  $ mkcommit I
  created new head
  $ hg push ../push-dest
  pushing to ../push-dest
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

:note: The "(+1 heads)" is wrong as we do not had any visible head

check that branch cache with "served" filter are properly computed and stored

  $ ls ../push-dest/.hg/cache/branch2*
  ../push-dest/.hg/cache/branch2-served
  $ cat ../push-dest/.hg/cache/branch2-served
  6d6770faffce199f1fddd1cf87f6f026138cf061 6 465891ffab3c47a3c23792f7dc84156e19a90722
  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e o default
  6d6770faffce199f1fddd1cf87f6f026138cf061 o default
  $ hg heads -R ../push-dest --template '{rev}:{node} {phase}\n'  #update visible cache too
  6:6d6770faffce199f1fddd1cf87f6f026138cf061 draft
  5:2713879da13d6eea1ff22b442a5a87cb31a7ce6a secret
  3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e draft
  $ ls ../push-dest/.hg/cache/branch2*
  ../push-dest/.hg/cache/branch2-served
  ../push-dest/.hg/cache/branch2-visible
  $ cat ../push-dest/.hg/cache/branch2-served
  6d6770faffce199f1fddd1cf87f6f026138cf061 6 465891ffab3c47a3c23792f7dc84156e19a90722
  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e o default
  6d6770faffce199f1fddd1cf87f6f026138cf061 o default
  $ cat ../push-dest/.hg/cache/branch2-visible
  6d6770faffce199f1fddd1cf87f6f026138cf061 6
  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e o default
  2713879da13d6eea1ff22b442a5a87cb31a7ce6a o default
  6d6770faffce199f1fddd1cf87f6f026138cf061 o default


Restore condition prior extra insertion.
  $ hg -q --config extensions.mq= strip .
  $ hg up -q 7
  $ cd ..

Test secret changeset are not pull

  $ hg init pull-dest
  $ cd pull-dest
  $ hg pull ../initialrepo
  pulling from ../initialrepo
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 5 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hglog
  4 0 B'
  3 0 D
  2 0 C
  1 0 B
  0 0 A
  $ cd ..

But secret can still be bundled explicitly

  $ cd initialrepo
  $ hg bundle --base '4^' -r 'children(4)' ../secret-bundle.hg
  4 changesets found
  $ cd ..

Test secret changeset are not cloned
(during local clone)

  $ hg clone -qU initialrepo clone-dest
  $ hglog -R clone-dest
  4 0 B'
  3 0 D
  2 0 C
  1 0 B
  0 0 A

Test summary

  $ hg summary -R clone-dest --verbose
  parent: -1:000000000000  (no revision checked out)
  branch: default
  commit: (clean)
  update: 5 new changesets (update)
  $ hg summary -R initialrepo
  parent: 7:17a481b3bccb tip
   merge B' and E
  branch: default
  commit: (clean) (secret)
  update: 1 new changesets, 2 branch heads (merge)
  phases: 3 draft, 3 secret
  $ hg summary -R initialrepo --quiet
  parent: 7:17a481b3bccb tip
  update: 1 new changesets, 2 branch heads (merge)

Test revset

  $ cd initialrepo
  $ hglog -r 'public()'
  0 0 A
  1 0 B
  $ hglog -r 'draft()'
  2 1 C
  3 1 D
  6 1 B'
  $ hglog -r 'secret()'
  4 2 E
  5 2 H
  7 2 merge B' and E

test that phase are displayed in log at debug level

  $ hg log --debug
  changeset:   7:17a481b3bccb796c0521ae97903d81c52bfee4af
  tag:         tip
  phase:       secret
  parent:      6:cf9fe039dfd67e829edf6522a45de057b5c86519
  parent:      4:a603bfb5a83e312131cebcd05353c217d4d21dde
  manifest:    7:5e724ffacba267b2ab726c91fc8b650710deaaa8
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      C D E
  extra:       branch=default
  description:
  merge B' and E
  
  
  changeset:   6:cf9fe039dfd67e829edf6522a45de057b5c86519
  phase:       draft
  parent:      1:27547f69f25460a52fff66ad004e58da7ad3fb56
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    6:ab8bfef2392903058bf4ebb9e7746e8d7026b27a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      B'
  extra:       branch=default
  description:
  B'
  
  
  changeset:   5:a030c6be5127abc010fcbff1851536552e6951a8
  phase:       secret
  parent:      4:a603bfb5a83e312131cebcd05353c217d4d21dde
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    5:5c710aa854874fe3d5fa7192e77bdb314cc08b5a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      H
  extra:       branch=default
  description:
  H
  
  
  changeset:   4:a603bfb5a83e312131cebcd05353c217d4d21dde
  phase:       secret
  parent:      3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    4:7173fd1c27119750b959e3a0f47ed78abe75d6dc
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      E
  extra:       branch=default
  description:
  E
  
  
  changeset:   3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  phase:       draft
  parent:      2:f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    3:6e1f4c47ecb533ffd0c8e52cdc88afb6cd39e20c
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      D
  extra:       branch=default
  description:
  D
  
  
  changeset:   2:f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  phase:       draft
  parent:      1:27547f69f25460a52fff66ad004e58da7ad3fb56
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    2:66a5a01817fdf5239c273802b5b7618d051c89e4
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      C
  extra:       branch=default
  description:
  C
  
  
  changeset:   1:27547f69f25460a52fff66ad004e58da7ad3fb56
  phase:       public
  parent:      0:4a2df7238c3b48766b5e22fafbb8a2f506ec8256
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    1:cb5cbbc1bfbf24cc34b9e8c16914e9caa2d2a7fd
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      B
  extra:       branch=default
  description:
  B
  
  
  changeset:   0:4a2df7238c3b48766b5e22fafbb8a2f506ec8256
  phase:       public
  parent:      -1:0000000000000000000000000000000000000000
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    0:007d8c9d88841325f5c6b06371b35b4e8a2b1a83
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      A
  extra:       branch=default
  description:
  A
  
  


(Issue3707)
test invalid phase name

  $ mkcommit I --config phases.new-commit='babar'
  transaction abort!
  rollback completed
  abort: phases.new-commit: not a valid phase name ('babar')
  [255]
Test phase command
===================

initial picture

  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 secret E
  | |
  o |  3 draft D
  | |
  o |  2 draft C
  |/
  o  1 public B
  |
  o  0 public A
  

display changesets phase

(mixing -r and plain rev specification)

  $ hg phase 1::4 -r 7
  1: public
  2: draft
  3: draft
  4: secret
  7: secret


move changeset forward

(with -r option)

  $ hg phase --public -r 2
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 secret E
  | |
  o |  3 draft D
  | |
  o |  2 public C
  |/
  o  1 public B
  |
  o  0 public A
  

move changeset backward

(without -r option)

  $ hg phase --draft --force 2
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 secret E
  | |
  o |  3 draft D
  | |
  o |  2 draft C
  |/
  o  1 public B
  |
  o  0 public A
  

move changeset forward and backward and test kill switch

  $ cat <<EOF >> $HGRCPATH
  > [experimental]
  > nativephaseskillswitch = true
  > EOF
  $ hg phase --draft --force 1::4
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 draft E
  | |
  o |  3 draft D
  | |
  o |  2 draft C
  |/
  o  1 draft B
  |
  o  0 public A
  
test partial failure

  $ cat <<EOF >> $HGRCPATH
  > [experimental]
  > nativephaseskillswitch = false
  > EOF
  $ hg phase --public 7
  $ hg phase --draft '5 or 7'
  cannot move 1 changesets to a higher phase, use --force
  phase changed for 1 changesets
  [1]
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 public merge B' and E
  |\
  | o  6 public B'
  | |
  +---o  5 draft H
  | |
  o |  4 public E
  | |
  o |  3 public D
  | |
  o |  2 public C
  |/
  o  1 public B
  |
  o  0 public A
  

test complete failure

  $ hg phase --draft 7
  cannot move 1 changesets to a higher phase, use --force
  no phases changed
  [1]

  $ cd ..

test hidden changeset are not cloned as public (issue3935)

  $ cd initialrepo

(enabling evolution)
  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > EOF

(making a changeset hidden; H in that case)
  $ hg debugobsolete `hg id --debug -r 5`

  $ cd ..
  $ hg clone initialrepo clonewithobs
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 7 changesets with 6 changes to 6 files
  updating to branch default
  6 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clonewithobs
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    6 public merge B' and E
  |\
  | o  5 public B'
  | |
  o |  4 public E
  | |
  o |  3 public D
  | |
  o |  2 public C
  |/
  o  1 public B
  |
  o  0 public A
  

test verify repo containing hidden changesets, which should not abort just
because repo.cancopy() is False

  $ cd ../initialrepo
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 8 changesets, 7 total revisions