view tests/test-convert-baz.t @ 38661:8ac0c9cd4c48

fncache: avoid loading the filename cache when not actually modifying it

With time, fncache can become very large. The mozilla-central repo for example,
has a 31M and growing fncache file. Loading this file takes time (280ms for the
mozilla-central repository).

In many scenarios, we don't need to load fncache at all. For example, when
committing changes to existing files, or pushing such commits to another clone.
This patch detects when a name is added via store.vfs(), and only loads the
cache if a) the data metadata file doesn't already exist, or b) when opening
for appending, the data or metadata file exists but has size  (a transaction
rollback leaves behind such files).

Benchmarks (run on Macos 10.13 on a 2017-model Macbook Pro with Core i7 2.9GHz
and flash drive), each test without and with patch run 5 times:

* committing to an existing file, against the mozilla-central repository.
  Baseline real time average 2.3736, with patch 1.9884.

* unbundling a large changeset consisting *only* of existing-file modifications
  (159 revisions, 1050 modifications, mozilla-central
  4a250a0e4f29:beea9ac7d823), into a clone limited to the ancestor revision of
  that revset). Baseline real time average 1.5048, with patch 1.3108.

#require baz symlink

  $ baz my-id "mercurial <[e-mail]>"

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "convert=" >> $HGRCPATH

create baz archive
  $ baz make-archive baz@mercurial--convert hg-test-convert-baz

initialize baz repo
  $ mkdir baz-repo
  $ cd baz-repo/
  $ baz init-tree baz@mercurial--convert/baz--test--0
  $ baz import
  * creating version baz@mercurial--convert/baz--test--0
  * imported baz@mercurial--convert/baz--test--0

create initial files
  $ echo 'this is a file' > a
  $ baz add a
  $ mkdir src
  $ baz add src
  $ cd src
  $ dd count=1 if=/dev/zero of=b > /dev/null 2> /dev/null
  $ baz add b
HACK: hide GNU tar-1.22 "tar: The --preserve option is deprecated, use --preserve-permissions --preserve-order instead"
  $ baz commit -s "added a file, src and src/b (binary)" 2>&1 | grep -v '^tar'
  * build pristine tree for baz@mercurial--convert/baz--test--0--base-0
  * Scanning for full-tree revision: .
  * from import revision: baz@mercurial--convert/baz--test--0--base-0
  A/ .arch-ids
  A/ src
  A/ src/.arch-ids
  A  .arch-ids/a.id
  A  a
  A  src/.arch-ids/=id
  A  src/.arch-ids/b.id
  A  src/b
  * update pristine tree (baz@mercurial--convert/baz--test--0--base-0 => baz--test--0--patch-1)
  * committed baz@mercurial--convert/baz--test--0--patch-1

create link file and modify a
  $ ln -s ../a a-link
  $ baz add a-link
  $ echo 'this a modification to a' >> ../a
  $ baz commit -s "added link to a and modify a"
  A  src/.arch-ids/a-link.id
  A  src/a-link
  M  a
  * update pristine tree (baz@mercurial--convert/baz--test--0--patch-1 => baz--test--0--patch-2)
  * committed baz@mercurial--convert/baz--test--0--patch-2

create second link and modify b
  $ ln -s ../a a-link-2
  $ baz add a-link-2
  $ dd count=1 seek=1 if=/dev/zero of=b > /dev/null 2> /dev/null
  $ baz commit -s "added second link and modify b"
  A  src/.arch-ids/a-link-2.id
  A  src/a-link-2
  Mb src/b
  * update pristine tree (baz@mercurial--convert/baz--test--0--patch-2 => baz--test--0--patch-3)
  * committed baz@mercurial--convert/baz--test--0--patch-3

b file to link and a-link-2 to regular file
  $ rm -f a-link-2
  $ echo 'this is now a regular file' > a-link-2
  $ ln -sf ../a b
  $ baz commit -s "file to link and link to file test"
  fl src/b
  lf src/a-link-2
  * update pristine tree (baz@mercurial--convert/baz--test--0--patch-3 => baz--test--0--patch-4)
  * committed baz@mercurial--convert/baz--test--0--patch-4

move a-link-2 file and src directory
  $ cd ..
  $ baz mv src/a-link-2 c
  $ baz mv src test
  $ baz commit -s "move and rename a-link-2 file and src directory"
  D/ src/.arch-ids
  A/ test/.arch-ids
  /> src	test
  => src/.arch-ids/a-link-2.id	.arch-ids/c.id
  => src/a-link-2	c
  => src/.arch-ids/=id	test/.arch-ids/=id
  => src/.arch-ids/a-link.id	test/.arch-ids/a-link.id
  => src/.arch-ids/b.id	test/.arch-ids/b.id
  * update pristine tree (baz@mercurial--convert/baz--test--0--patch-4 => baz--test--0--patch-5)
  * committed baz@mercurial--convert/baz--test--0--patch-5

move and add the moved file again
  $ echo e > e
  $ baz add e
  $ baz commit -s "add e"
  A  .arch-ids/e.id
  A  e
  * update pristine tree (baz@mercurial--convert/baz--test--0--patch-5 => baz--test--0--patch-6)
  * committed baz@mercurial--convert/baz--test--0--patch-6
  $ baz mv e f
  $ echo ee > e
  $ baz add e
  $ baz commit -s "move e and recreate it again"
  A  .arch-ids/e.id
  A  e
  => .arch-ids/e.id	.arch-ids/f.id
  => e	f
  * update pristine tree (baz@mercurial--convert/baz--test--0--patch-6 => baz--test--0--patch-7)
  * committed baz@mercurial--convert/baz--test--0--patch-7
  $ cd ..

converting baz repo to Mercurial
  $ hg convert baz-repo baz-repo-hg
  initializing destination baz-repo-hg repository
  analyzing tree version baz@mercurial--convert/baz--test--0...
  scanning source...
  sorting...
  converting...
  7 initial import
  6 added a file, src and src/b (binary)
  5 added link to a and modify a
  4 added second link and modify b
  3 file to link and link to file test
  2 move and rename a-link-2 file and src directory
  1 add e
  0 move e and recreate it again

  $ baz register-archive -d baz@mercurial--convert

  $ glog()
  > {
  >     hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
  > }

show graph log
  $ glog -R baz-repo-hg
  o  7 "move e and recreate it again" files: e f
  |
  o  6 "add e" files: e
  |
  o  5 "move and rename a-link-2 file and src directory" files: c src/a-link src/a-link-2 src/b test/a-link test/b
  |
  o  4 "file to link and link to file test" files: src/a-link-2 src/b
  |
  o  3 "added second link and modify b" files: src/a-link-2 src/b
  |
  o  2 "added link to a and modify a" files: a src/a-link
  |
  o  1 "added a file, src and src/b (binary)" files: a src/b
  |
  o  0 "initial import" files:
  
  $ hg up -q -R baz-repo-hg
  $ hg -R baz-repo-hg manifest --debug
  c4072c4b72e1cabace081888efa148ee80ca3cbb 644   a
  0201ac32a3a8e86e303dff60366382a54b48a72e 644   c
  1a4a864db0073705a11b1439f563bfa4b46d9246 644   e
  09e0222742fc3f75777fa9d68a5d8af7294cb5e7 644   f
  c0067ba5ff0b7c9a3eb17270839d04614c435623 644 @ test/a-link
  375f4263d86feacdea7e3c27100abd1560f2a973 644 @ test/b
  $ hg -R baz-repo-hg log -r 5 -r 7 -C --debug | grep copies
  copies:      c (src/a-link-2) test/a-link (src/a-link) test/b (src/b)
  copies:      f (e)