view tests/test-verify.t @ 33207:895ecec31c70

revlog: add an experimental option to mitigated delta issues (issue5480)

The general delta heuristic to select a delta do not scale with the number of
branch. The delta base is frequently too far away to be able to reuse a chain
according to the "distance" criteria. This leads to insertion of larger delta (or
even full text) that themselves push the bases for the next delta further away
leading to more large deltas and full texts. This full text and frequent
recomputation throw Mercurial performance in disarray.

For example of a slightly large repository

  280 000 files (2 150 000 versions)
  430 000 changesets (10 000 topological heads)

Number below compares repository with and without the distance criteria:

manifest size:
    with:    21.4 GB
    without:  0.3 GB

store size:
    with:    28.7 GB
    without   7.4 GB

bundle last 15 00 revisions:
    with:    800 seconds
             971 MB
    without:  50 seconds
              73 MB

unbundle time (of the last 15K revisions):
    with:    1150 seconds (~19 minutes)
    without:   35 seconds

Similar issues has been observed in other repositories.


Adding a new option or "feature" on stable is uncommon. However, given that this
issues is making Mercurial practically unusable, I'm exceptionally targeting
this patch for stable.

What is actually needed is a full rework of the delta building and reading
logic. However, that will be a longer process and churn not suitable for stable.

In the meantime, we introduces a quick and dirty mitigation of this in the
'experimental' config space. The new option introduces a way to set the maximum
amount of memory usable to store a diff in memory. This extend the ability for
Mercurial to create chains without removing all safe guard regarding memory
access. The option should be phased out when core has a more proper solution
available.

Setting the limit to '0' remove all limits, setting it to '-1' use the default
limit (textsize x 4).

prepare repo

  $ hg init a
  $ cd a
  $ echo "some text" > FOO.txt
  $ echo "another text" > bar.txt
  $ echo "more text" > QUICK.txt
  $ hg add
  adding FOO.txt
  adding QUICK.txt
  adding bar.txt
  $ hg ci -mtest1

verify

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 1 changesets, 3 total revisions

verify with journal

  $ touch .hg/store/journal
  $ hg verify
  abandoned transaction found - run hg recover
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 1 changesets, 3 total revisions
  $ rm .hg/store/journal

introduce some bugs in repo

  $ cd .hg/store/data
  $ mv _f_o_o.txt.i X_f_o_o.txt.i
  $ mv bar.txt.i xbar.txt.i
  $ rm _q_u_i_c_k.txt.i

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
   warning: revlog 'data/FOO.txt.i' not in fncache!
   0: empty or missing FOO.txt
   FOO.txt@0: manifest refers to unknown revision f62022d3d590
   warning: revlog 'data/QUICK.txt.i' not in fncache!
   0: empty or missing QUICK.txt
   QUICK.txt@0: manifest refers to unknown revision 88b857db8eba
   warning: revlog 'data/bar.txt.i' not in fncache!
   0: empty or missing bar.txt
   bar.txt@0: manifest refers to unknown revision 256559129457
  3 files, 1 changesets, 0 total revisions
  3 warnings encountered!
  hint: run "hg debugrebuildfncache" to recover from corrupt fncache
  6 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]

  $ cd ../../..
  $ cd ..

Set up a repo for testing missing revlog entries

  $ hg init missing-entries
  $ cd missing-entries
  $ echo 0 > file
  $ hg ci -Aqm0
  $ cp -R .hg/store .hg/store-partial
  $ echo 1 > file
  $ hg ci -Aqm1
  $ cp -R .hg/store .hg/store-full

Entire changelog missing

  $ rm .hg/store/00changelog.*
  $ hg verify -q
   0: empty or missing changelog
   manifest@0: d0b6632564d4 not in changesets
   manifest@1: 941fc4534185 not in changesets
  3 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Entire manifest log missing

  $ rm .hg/store/00manifest.*
  $ hg verify -q
   0: empty or missing manifest
  1 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Entire filelog missing

  $ rm .hg/store/data/file.*
  $ hg verify -q
   warning: revlog 'data/file.i' not in fncache!
   0: empty or missing file
   file@0: manifest refers to unknown revision 362fef284ce2
   file@1: manifest refers to unknown revision c10f2164107d
  1 warnings encountered!
  hint: run "hg debugrebuildfncache" to recover from corrupt fncache
  3 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Entire changelog and manifest log missing

  $ rm .hg/store/00changelog.*
  $ rm .hg/store/00manifest.*
  $ hg verify -q
  warning: orphan revlog 'data/file.i'
  1 warnings encountered!
  $ cp -R .hg/store-full/. .hg/store

Entire changelog and filelog missing

  $ rm .hg/store/00changelog.*
  $ rm .hg/store/data/file.*
  $ hg verify -q
   0: empty or missing changelog
   manifest@0: d0b6632564d4 not in changesets
   manifest@1: 941fc4534185 not in changesets
   warning: revlog 'data/file.i' not in fncache!
   ?: empty or missing file
   file@0: manifest refers to unknown revision 362fef284ce2
   file@1: manifest refers to unknown revision c10f2164107d
  1 warnings encountered!
  hint: run "hg debugrebuildfncache" to recover from corrupt fncache
  6 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Entire manifest log and filelog missing

  $ rm .hg/store/00manifest.*
  $ rm .hg/store/data/file.*
  $ hg verify -q
   0: empty or missing manifest
   warning: revlog 'data/file.i' not in fncache!
   0: empty or missing file
  1 warnings encountered!
  hint: run "hg debugrebuildfncache" to recover from corrupt fncache
  2 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Changelog missing entry

  $ cp -f .hg/store-partial/00changelog.* .hg/store
  $ hg verify -q
   manifest@?: rev 1 points to nonexistent changeset 1
   manifest@?: 941fc4534185 not in changesets
   file@?: rev 1 points to nonexistent changeset 1
   (expected 0)
  1 warnings encountered!
  3 integrity errors encountered!
  [1]
  $ cp -R .hg/store-full/. .hg/store

Manifest log missing entry

  $ cp -f .hg/store-partial/00manifest.* .hg/store
  $ hg verify -q
   manifest@1: changeset refers to unknown revision 941fc4534185
   file@1: c10f2164107d not in manifests
  2 integrity errors encountered!
  (first damaged changeset appears to be 1)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Filelog missing entry

  $ cp -f .hg/store-partial/data/file.* .hg/store/data
  $ hg verify -q
   file@1: manifest refers to unknown revision c10f2164107d
  1 integrity errors encountered!
  (first damaged changeset appears to be 1)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Changelog and manifest log missing entry

  $ cp -f .hg/store-partial/00changelog.* .hg/store
  $ cp -f .hg/store-partial/00manifest.* .hg/store
  $ hg verify -q
   file@?: rev 1 points to nonexistent changeset 1
   (expected 0)
   file@?: c10f2164107d not in manifests
  1 warnings encountered!
  2 integrity errors encountered!
  [1]
  $ cp -R .hg/store-full/. .hg/store

Changelog and filelog missing entry

  $ cp -f .hg/store-partial/00changelog.* .hg/store
  $ cp -f .hg/store-partial/data/file.* .hg/store/data
  $ hg verify -q
   manifest@?: rev 1 points to nonexistent changeset 1
   manifest@?: 941fc4534185 not in changesets
   file@?: manifest refers to unknown revision c10f2164107d
  3 integrity errors encountered!
  [1]
  $ cp -R .hg/store-full/. .hg/store

Manifest and filelog missing entry

  $ cp -f .hg/store-partial/00manifest.* .hg/store
  $ cp -f .hg/store-partial/data/file.* .hg/store/data
  $ hg verify -q
   manifest@1: changeset refers to unknown revision 941fc4534185
  1 integrity errors encountered!
  (first damaged changeset appears to be 1)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Corrupt changelog base node to cause failure to read revision

  $ printf abcd | dd conv=notrunc of=.hg/store/00changelog.i bs=1 seek=16 \
  >   2> /dev/null
  $ hg verify -q
   0: unpacking changeset 08b1860757c2: * (glob)
   manifest@?: rev 0 points to unexpected changeset 0
   manifest@?: d0b6632564d4 not in changesets
   file@?: rev 0 points to unexpected changeset 0
   (expected 1)
  1 warnings encountered!
  4 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Corrupt manifest log base node to cause failure to read revision

  $ printf abcd | dd conv=notrunc of=.hg/store/00manifest.i bs=1 seek=16 \
  >   2> /dev/null
  $ hg verify -q
   manifest@0: reading delta d0b6632564d4: * (glob)
   file@0: 362fef284ce2 not in manifests
  2 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

Corrupt filelog base node to cause failure to read revision

  $ printf abcd | dd conv=notrunc of=.hg/store/data/file.i bs=1 seek=16 \
  >   2> /dev/null
  $ hg verify -q
   file@0: unpacking 362fef284ce2: * (glob)
  1 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ cp -R .hg/store-full/. .hg/store

  $ cd ..

test changelog without a manifest

  $ hg init b
  $ cd b
  $ hg branch foo
  marked working directory as branch foo
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -m branchfoo
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 1 changesets, 0 total revisions

test revlog corruption

  $ touch a
  $ hg add a
  $ hg ci -m a

  $ echo 'corrupted' > b
  $ dd if=.hg/store/data/a.i of=start bs=1 count=20 2>/dev/null
  $ cat start b > .hg/store/data/a.i

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
   a@1: broken revlog! (index data/a.i is corrupted)
  warning: orphan revlog 'data/a.i'
  1 files, 2 changesets, 0 total revisions
  1 warnings encountered!
  1 integrity errors encountered!
  (first damaged changeset appears to be 1)
  [1]

  $ cd ..

test revlog format 0

  $ revlog-formatv0.py
  $ cd formatv0
  $ hg verify
  repository uses revlog format 0
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions
  $ cd ..

test flag processor and skipflags

  $ hg init skipflags
  $ cd skipflags
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > flagprocessor=$RUNTESTDIR/flagprocessorext.py
  > EOF
  $ echo '[BASE64]content' > base64
  $ hg commit -Aqm 'flag processor content' base64
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions

  $ cat >> $TESTTMP/break-base64.py <<EOF
  > from __future__ import absolute_import
  > import base64
  > base64.b64decode=lambda x: x
  > EOF
  $ cat >> .hg/hgrc <<EOF
  > breakbase64=$TESTTMP/break-base64.py
  > EOF

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
   base64@0: unpacking 794cee7777cb: integrity check failed on data/base64.i:0
  1 files, 1 changesets, 1 total revisions
  1 integrity errors encountered!
  (first damaged changeset appears to be 0)
  [1]
  $ hg verify --config verify.skipflags=2147483647
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions