annotate tests/test-remotefilelog-repack.t @ 43256:00de32aa834e

copies: use an unfiltered repository for the changeset centric algorithm

Since the algorithm work form heads to ancestors, we don't need to check
filtering for anything but the two entries.

Using an unfiltered version is noticeably more efficient.

Some timing on the pypy repo:
revision: large amount; added files: large amount; rename small amount; c3b14617fbd7 9ba6ab77fd29
before: ! wall 2.717861 comb 2.720000 user 2.700000 sys 0.020000 (median of 10)
after:  ! wall 2.582204 comb 2.580000 user 2.560000 sys 0.020000 (median of 10)
revision: large amount; added files: small amount; rename small amount; c3b14617fbd7 f650a9b140d2
before: ! wall 4.003146 comb 4.010000 user 3.970000 sys 0.040000 (median of 10)
after:  ! wall 3.814613 comb 3.810000 user 3.760000 sys 0.050000 (median of 10)
revision: large amount; added files: large amount; rename large amount; 08ea3258278e d9fa043f30c0
before: ! wall 0.704204 comb 0.700000 user 0.700000 sys 0.000000 (median of 13)
after:  ! wall 0.657387 comb 0.650000 user 0.640000 sys 0.010000 (best of 14)
revision: small amount; added files: large amount; rename large amount; df6f7a526b60 a83dc6a2d56f
before: ! wall 0.013493 comb 0.020000 user 0.020000 sys 0.000000 (median of 219)
after:  ! wall 0.013523 comb 0.020000 user 0.020000 sys 0.000000 (median of 218)
revision: small amount; added files: large amount; rename small amount; 4aa4e1f8e19a 169138063d63
before: ! wall 0.003017 comb 0.000000 user 0.000000 sys 0.000000 (median of 985)
after:  ! wall 0.002876 comb 0.000000 user 0.000000 sys 0.000000 (median of 1000)
revision: small amount; added files: small amount; rename small amount; 4bc173b045a6 964879152e2e
before: ! wall 0.000073 comb 0.000000 user 0.000000 sys 0.000000 (median of 12672)
after:  ! wall 0.000082 comb 0.000000 user 0.000000 sys 0.000000 (median of 11456)
revision: medium amount; added files: large amount; rename medium amount; c95f1ced15f2 2c68e87c3efe
before: ! wall 0.478061 comb 0.470000 user 0.470000 sys 0.000000 (median of 19)
after:  ! wall 0.452420 comb 0.450000 user 0.450000 sys 0.000000 (median of 21)
revision: medium amount; added files: medium amount; rename small amount; d343da0c55a8 d7746d32bf9d
before: ! wall 0.116015 comb 0.110000 user 0.110000 sys 0.000000 (median of 84)
after:  ! wall 0.109153 comb 0.100000 user 0.100000 sys 0.000000 (median of 90)

Differential Revision: https://phab.mercurial-scm.org/D7123

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"
# devel.remotefilelog.ensurestart: reduce race condition with
# waiton{repack/prefetch}
  $ cat >> $HGRCPATH <<EOF
  > [devel]
  > remotefilelog.ensurestart=True
  > EOF

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > serverexpiration=-1
  > EOF
  $ echo x > x
  $ hg commit -qAm x
  $ echo x >> x
  $ hg commit -qAm x2
  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow -q
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)

# Set the prefetchdays config to zero so that all commits are prefetched
# no matter what their creation date is.
  $ cd shallow
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > prefetchdays=0
  > EOF
  $ cd ..

# Test that repack cleans up the old files and creates new packs

  $ cd shallow
  $ find $CACHEDIR | sort
  $TESTTMP/hgcache
  $TESTTMP/hgcache/master
  $TESTTMP/hgcache/master/11
  $TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072
  $TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/aee31534993a501858fb6dd96a065671922e7d51
  $TESTTMP/hgcache/repos

  $ hg repack

  $ find $CACHEDIR | sort
  $TESTTMP/hgcache
  $TESTTMP/hgcache/master
  $TESTTMP/hgcache/master/packs
  $TESTTMP/hgcache/master/packs/1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histidx
  $TESTTMP/hgcache/master/packs/1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histpack
  $TESTTMP/hgcache/master/packs/b1e0cfc7f345e408a7825e3081501959488d59ce.dataidx
  $TESTTMP/hgcache/master/packs/b1e0cfc7f345e408a7825e3081501959488d59ce.datapack
  $TESTTMP/hgcache/repos

# Test that the packs are readonly
  $ ls_l $CACHEDIR/master/packs
  -r--r--r--    1145 1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histidx
  -r--r--r--     172 1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histpack
  -r--r--r--    1074 b1e0cfc7f345e408a7825e3081501959488d59ce.dataidx
  -r--r--r--      72 b1e0cfc7f345e408a7825e3081501959488d59ce.datapack

# Test that the data in the new packs is accessible
  $ hg cat -r . x
  x
  x

# Test that adding new data and repacking it results in the loose data and the
# old packs being combined.

  $ cd ../master
  $ echo x >> x
  $ hg commit -m x3
  $ cd ../shallow
  $ hg pull -q
  $ hg up -q tip
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)

  $ find $CACHEDIR -type f | sort
  $TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/d4a3ed9310e5bd9887e3bf779da5077efab28216
  $TESTTMP/hgcache/master/packs/1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histidx
  $TESTTMP/hgcache/master/packs/1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histpack
  $TESTTMP/hgcache/master/packs/b1e0cfc7f345e408a7825e3081501959488d59ce.dataidx
  $TESTTMP/hgcache/master/packs/b1e0cfc7f345e408a7825e3081501959488d59ce.datapack
  $TESTTMP/hgcache/repos

# First assert that with --packsonly, the loose object will be ignored:

  $ hg repack --packsonly

  $ find $CACHEDIR -type f | sort
  $TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/d4a3ed9310e5bd9887e3bf779da5077efab28216
  $TESTTMP/hgcache/master/packs/1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histidx
  $TESTTMP/hgcache/master/packs/1e91b207daf5d7b48f1be9c587d6b5ae654ce78c.histpack
  $TESTTMP/hgcache/master/packs/b1e0cfc7f345e408a7825e3081501959488d59ce.dataidx
  $TESTTMP/hgcache/master/packs/b1e0cfc7f345e408a7825e3081501959488d59ce.datapack
  $TESTTMP/hgcache/repos

  $ hg repack --traceback

  $ find $CACHEDIR -type f | sort
  $TESTTMP/hgcache/master/packs/78840d69389c7404327f7477e3931c89945c37d1.dataidx
  $TESTTMP/hgcache/master/packs/78840d69389c7404327f7477e3931c89945c37d1.datapack
  $TESTTMP/hgcache/master/packs/8abe7889aae389337d12ebe6085d4ee13854c7c9.histidx
  $TESTTMP/hgcache/master/packs/8abe7889aae389337d12ebe6085d4ee13854c7c9.histpack
  $TESTTMP/hgcache/repos

# Verify all the file data is still available
  $ hg cat -r . x
  x
  x
  x
  $ hg cat -r '.^' x
  x
  x

# Test that repacking again without new data does not delete the pack files
# and did not change the pack names
  $ hg repack
  $ find $CACHEDIR -type f | sort
  $TESTTMP/hgcache/master/packs/78840d69389c7404327f7477e3931c89945c37d1.dataidx
  $TESTTMP/hgcache/master/packs/78840d69389c7404327f7477e3931c89945c37d1.datapack
  $TESTTMP/hgcache/master/packs/8abe7889aae389337d12ebe6085d4ee13854c7c9.histidx
  $TESTTMP/hgcache/master/packs/8abe7889aae389337d12ebe6085d4ee13854c7c9.histpack
  $TESTTMP/hgcache/repos

# Run two repacks at once
  $ hg repack --config "hooks.prerepack=sleep 3" &
  $ sleep 1
  $ hg repack
  skipping repack - another repack is already running
  $ hg debugwaitonrepack >/dev/null 2>&1

# Run repack in the background
  $ cd ../master
  $ echo x >> x
  $ hg commit -m x4
  $ cd ../shallow
  $ hg pull -q
  $ hg up -q tip
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ find $CACHEDIR -type f | sort
  $TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1bb2e6237e035c8f8ef508e281f1ce075bc6db72
  $TESTTMP/hgcache/master/packs/78840d69389c7404327f7477e3931c89945c37d1.dataidx
  $TESTTMP/hgcache/master/packs/78840d69389c7404327f7477e3931c89945c37d1.datapack
  $TESTTMP/hgcache/master/packs/8abe7889aae389337d12ebe6085d4ee13854c7c9.histidx
  $TESTTMP/hgcache/master/packs/8abe7889aae389337d12ebe6085d4ee13854c7c9.histpack
  $TESTTMP/hgcache/repos

  $ hg repack --background
  (running background repack)
  $ sleep 0.5
  $ hg debugwaitonrepack >/dev/null 2>&1
  $ find $CACHEDIR -type f | sort
  $TESTTMP/hgcache/master/packs/39443fa1064182e93d968b5cba292eb5283260d0.dataidx
  $TESTTMP/hgcache/master/packs/39443fa1064182e93d968b5cba292eb5283260d0.datapack
  $TESTTMP/hgcache/master/packs/604552d403a1381749faf656feca0ca265a6d52c.histidx
  $TESTTMP/hgcache/master/packs/604552d403a1381749faf656feca0ca265a6d52c.histpack
  $TESTTMP/hgcache/repos

# Test debug commands

  $ hg debugdatapack $TESTTMP/hgcache/master/packs/*.datapack
  $TESTTMP/hgcache/master/packs/39443fa1064182e93d968b5cba292eb5283260d0:
  x:
  Node          Delta Base    Delta Length  Blob Size
  1bb2e6237e03  000000000000  8             8
  d4a3ed9310e5  1bb2e6237e03  12            6
  aee31534993a  d4a3ed9310e5  12            4
  
  Total:                      32            18        (77.8% bigger)
  $ hg debugdatapack --long $TESTTMP/hgcache/master/packs/*.datapack
  $TESTTMP/hgcache/master/packs/39443fa1064182e93d968b5cba292eb5283260d0:
  x:
  Node                                      Delta Base                                Delta Length  Blob Size
  1bb2e6237e035c8f8ef508e281f1ce075bc6db72  0000000000000000000000000000000000000000  8             8
  d4a3ed9310e5bd9887e3bf779da5077efab28216  1bb2e6237e035c8f8ef508e281f1ce075bc6db72  12            6
  aee31534993a501858fb6dd96a065671922e7d51  d4a3ed9310e5bd9887e3bf779da5077efab28216  12            4
  
  Total:                                                                              32            18        (77.8% bigger)
  $ hg debugdatapack $TESTTMP/hgcache/master/packs/*.datapack --node d4a3ed9310e5bd9887e3bf779da5077efab28216
  $TESTTMP/hgcache/master/packs/39443fa1064182e93d968b5cba292eb5283260d0:
  
  x
  Node                                      Delta Base                                Delta SHA1                                Delta Length
  d4a3ed9310e5bd9887e3bf779da5077efab28216  1bb2e6237e035c8f8ef508e281f1ce075bc6db72  77029ab56e83ea2115dd53ff87483682abe5d7ca  12
  Node                                      Delta Base                                Delta SHA1                                Delta Length
  1bb2e6237e035c8f8ef508e281f1ce075bc6db72  0000000000000000000000000000000000000000  7ca8c71a64f7b56380e77573da2f7a5fdd2ecdb5  8
  $ hg debughistorypack $TESTTMP/hgcache/master/packs/*.histidx
  
  x
  Node          P1 Node       P2 Node       Link Node     Copy From
  1bb2e6237e03  d4a3ed9310e5  000000000000  0b03bbc9e1e7  
  d4a3ed9310e5  aee31534993a  000000000000  421535db10b6  
  aee31534993a  1406e7411862  000000000000  a89d614e2364  
  1406e7411862  000000000000  000000000000  b292c1e3311f  

# Test copy tracing from a pack
  $ cd ../master
  $ hg mv x y
  $ hg commit -m 'move x to y'
  $ cd ../shallow
  $ hg pull -q
  $ hg up -q tip
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ hg repack
  $ hg log -f y -T '{desc}\n'
  move x to y
  x4
  x3
  x2
  x

# Test copy trace across rename and back
  $ cp -R $TESTTMP/hgcache/master/packs $TESTTMP/backuppacks
  $ cd ../master
  $ hg mv y x
  $ hg commit -m 'move y back to x'
  $ hg revert -r 0 x
  $ mv x y
  $ hg add y
  $ echo >> y
  $ hg revert x
  $ hg commit -m 'add y back without metadata'
  $ cd ../shallow
  $ hg pull -q
  $ hg up -q tip
  2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over * (glob)
  $ hg repack
  $ ls $TESTTMP/hgcache/master/packs
  bfd60adb76018bb952e27cd23fc151bf94865d7d.histidx
  bfd60adb76018bb952e27cd23fc151bf94865d7d.histpack
  fb3aa57b22789ebcc45706c352e2d6af099c5816.dataidx
  fb3aa57b22789ebcc45706c352e2d6af099c5816.datapack
  $ hg debughistorypack $TESTTMP/hgcache/master/packs/*.histidx
  
  x
  Node          P1 Node       P2 Node       Link Node     Copy From
  cd410a44d584  577959738234  000000000000  609547eda446  y
  1bb2e6237e03  d4a3ed9310e5  000000000000  0b03bbc9e1e7  
  d4a3ed9310e5  aee31534993a  000000000000  421535db10b6  
  aee31534993a  1406e7411862  000000000000  a89d614e2364  
  1406e7411862  000000000000  000000000000  b292c1e3311f  
  
  y
  Node          P1 Node       P2 Node       Link Node     Copy From
  577959738234  1bb2e6237e03  000000000000  c7faf2fc439a  x
  21f46f2721e7  000000000000  000000000000  d6868642b790  
  $ hg strip -r '.^'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/609547eda446-b26b56a8-backup.hg (glob)
  $ hg -R ../master strip -r '.^'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/master/.hg/strip-backup/609547eda446-b26b56a8-backup.hg (glob)

  $ rm -rf $TESTTMP/hgcache/master/packs
  $ cp -R $TESTTMP/backuppacks $TESTTMP/hgcache/master/packs

# Test repacking datapack without history
  $ rm -rf $CACHEDIR/master/packs/*hist*
  $ hg repack
  $ hg debugdatapack $TESTTMP/hgcache/master/packs/*.datapack
  $TESTTMP/hgcache/master/packs/922aca43dbbeda4d250565372e8892ec7b08da6a:
  x:
  Node          Delta Base    Delta Length  Blob Size
  1bb2e6237e03  000000000000  8             8
  d4a3ed9310e5  1bb2e6237e03  12            6
  aee31534993a  d4a3ed9310e5  12            4
  
  Total:                      32            18        (77.8% bigger)
  y:
  Node          Delta Base    Delta Length  Blob Size
  577959738234  000000000000  70            8
  
  Total:                      70            8         (775.0% bigger)

  $ hg cat -r ".^" x
  x
  x
  x
  x

Incremental repack
  $ rm -rf $CACHEDIR/master/packs/*
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > data.generations=60
  >   150
  > EOF

Single pack - repack does nothing
  $ hg prefetch -r 0
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  [1]
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  [1]
  $ hg repack --incremental
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  -r--r--r--      70 052643fdcdebbd42d7c180a651a30d46098e6fe1.datapack
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  -r--r--r--      90 955a622173324b2d8b53e1147f209f1cf125302e.histpack

3 gen1 packs, 1 gen0 pack - packs 3 gen1 into 1
  $ hg prefetch -r 1
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ hg prefetch -r 2
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ hg prefetch -r 38
  abort: unknown revision '38'!
  [255]
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  -r--r--r--      70 052643fdcdebbd42d7c180a651a30d46098e6fe1.datapack
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  -r--r--r--      90 955a622173324b2d8b53e1147f209f1cf125302e.histpack

For the data packs, setting the limit for the repackmaxpacksize to be 64 such
that data pack with size 65 is more than the limit. This effectively ensures
that no generation has 3 packs and therefore, no packs are chosen for the
incremental repacking. As for the history packs, setting repackmaxpacksize to be
0 which should always result in no repacking.
  $ hg repack --incremental --config remotefilelog.data.repackmaxpacksize=64 \
  > --config remotefilelog.history.repackmaxpacksize=0
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  -r--r--r--      70 052643fdcdebbd42d7c180a651a30d46098e6fe1.datapack
  -r--r--r--     149 78840d69389c7404327f7477e3931c89945c37d1.datapack
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  -r--r--r--     254 8abe7889aae389337d12ebe6085d4ee13854c7c9.histpack
  -r--r--r--      90 955a622173324b2d8b53e1147f209f1cf125302e.histpack

Setting limit for the repackmaxpacksize to be the size of the biggest pack file
which ensures that it is effectively ignored in the incremental repacking.
  $ hg repack --incremental --config remotefilelog.data.repackmaxpacksize=65 \
  > --config remotefilelog.history.repackmaxpacksize=336
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  -r--r--r--      70 052643fdcdebbd42d7c180a651a30d46098e6fe1.datapack
  -r--r--r--     149 78840d69389c7404327f7477e3931c89945c37d1.datapack
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  -r--r--r--     254 8abe7889aae389337d12ebe6085d4ee13854c7c9.histpack
  -r--r--r--      90 955a622173324b2d8b53e1147f209f1cf125302e.histpack

1 gen3 pack, 1 gen0 pack - does nothing
  $ hg repack --incremental
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  -r--r--r--      70 052643fdcdebbd42d7c180a651a30d46098e6fe1.datapack
  -r--r--r--     149 78840d69389c7404327f7477e3931c89945c37d1.datapack
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  -r--r--r--     254 8abe7889aae389337d12ebe6085d4ee13854c7c9.histpack
  -r--r--r--      90 955a622173324b2d8b53e1147f209f1cf125302e.histpack

Pull should run background repack
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > backgroundrepack=True
  > EOF
  $ clearcache
  $ hg prefetch -r 0
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ hg prefetch -r 1
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ hg prefetch -r 2
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ hg prefetch -r 3
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)

  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  no changes found
  (running background incremental repack)
  $ sleep 0.5
  $ hg debugwaitonrepack >/dev/null 2>&1
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep datapack
  -r--r--r--     303 156a6c1c83aeb69422d7936e0a46ba9bc06a71c0.datapack
  $ ls_l $TESTTMP/hgcache/master/packs/ | grep histpack
  -r--r--r--     336 604552d403a1381749faf656feca0ca265a6d52c.histpack

Test environment variable resolution
  $ CACHEPATH=$TESTTMP/envcache hg prefetch --config 'remotefilelog.cachepath=$CACHEPATH'
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ find $TESTTMP/envcache | sort
  $TESTTMP/envcache
  $TESTTMP/envcache/master
  $TESTTMP/envcache/master/95
  $TESTTMP/envcache/master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a
  $TESTTMP/envcache/master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/577959738234a1eb241ed3ed4b22a575833f56e0
  $TESTTMP/envcache/repos

Test local remotefilelog blob is correct when based on a pack
  $ hg prefetch -r .
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ echo >> y
  $ hg commit -m y2
  $ hg debugremotefilelog .hg/store/data/95cb0bfd2977c761298d9624e4b4d4c72a39974a/b70860edba4f8242a1d52f2a94679dd23cb76808
  size: 9 bytes
  path: .hg/store/data/95cb0bfd2977c761298d9624e4b4d4c72a39974a/b70860edba4f8242a1d52f2a94679dd23cb76808 
  key: b70860edba4f 
  
          node =>           p1            p2      linknode     copyfrom
  b70860edba4f => 577959738234  000000000000  08d3fbc98c48  
  577959738234 => 1bb2e6237e03  000000000000  c7faf2fc439a  x
  1bb2e6237e03 => d4a3ed9310e5  000000000000  0b03bbc9e1e7  
  d4a3ed9310e5 => aee31534993a  000000000000  421535db10b6  
  aee31534993a => 1406e7411862  000000000000  a89d614e2364  
  1406e7411862 => 000000000000  000000000000  b292c1e3311f  

Test limiting the max delta chain length
  $ hg repack --config packs.maxchainlen=1
  $ hg debugdatapack $TESTTMP/hgcache/master/packs/*.dataidx
  $TESTTMP/hgcache/master/packs/f258af4c033dd5cd32b4dbc42a1efcd8e4c7d909:
  x:
  Node          Delta Base    Delta Length  Blob Size
  1bb2e6237e03  000000000000  8             8
  d4a3ed9310e5  1bb2e6237e03  12            6
  aee31534993a  000000000000  4             4
  1406e7411862  aee31534993a  12            2
  
  Total:                      36            20        (80.0% bigger)
  y:
  Node          Delta Base    Delta Length  Blob Size
  577959738234  000000000000  70            8
  
  Total:                      70            8         (775.0% bigger)

Test huge pack cleanup using different values of packs.maxpacksize:
  $ hg repack --incremental --debug
  $ hg repack --incremental --debug --config packs.maxpacksize=512
  removing oversize packfile $TESTTMP/hgcache/master/packs/f258af4c033dd5cd32b4dbc42a1efcd8e4c7d909.datapack (425 bytes)
  removing oversize packfile $TESTTMP/hgcache/master/packs/f258af4c033dd5cd32b4dbc42a1efcd8e4c7d909.dataidx (1.21 KB)

Do a repack where the new pack reuses a delta from the old pack
  $ clearcache
  $ hg prefetch -r '2::3'
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over * (glob)
  $ hg repack
  $ hg debugdatapack $CACHEDIR/master/packs/*.datapack
  $TESTTMP/hgcache/master/packs/9ec6b30891bd851320acb7c66b69a2bdf41c8df3:
  x:
  Node          Delta Base    Delta Length  Blob Size
  1bb2e6237e03  000000000000  8             8
  d4a3ed9310e5  1bb2e6237e03  12            6
  
  Total:                      20            14        (42.9% bigger)
  $ hg prefetch -r '0::1'
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over * (glob)
  $ hg repack
  $ hg debugdatapack $CACHEDIR/master/packs/*.datapack
  $TESTTMP/hgcache/master/packs/156a6c1c83aeb69422d7936e0a46ba9bc06a71c0:
  x:
  Node          Delta Base    Delta Length  Blob Size
  1bb2e6237e03  000000000000  8             8
  d4a3ed9310e5  1bb2e6237e03  12            6
  aee31534993a  d4a3ed9310e5  12            4
  1406e7411862  aee31534993a  12            2
  
  Total:                      44            20        (120.0% bigger)