view tests/test-clone-r.t @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

  $ hg init test
  $ cd test

  $ echo 0 >> afile
  $ hg add afile
  $ hg commit -m "0.0"

  $ echo 1 >> afile
  $ hg commit -m "0.1"

  $ echo 2 >> afile
  $ hg commit -m "0.2"

  $ echo 3 >> afile
  $ hg commit -m "0.3"

  $ hg update -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo 1 >> afile
  $ hg commit -m "1.1"
  created new head

  $ echo 2 >> afile
  $ hg commit -m "1.2"

  $ echo a line > fred
  $ echo 3 >> afile
  $ hg add fred
  $ hg commit -m "1.3"
  $ hg mv afile adifferentfile
  $ hg commit -m "1.3m"

  $ hg update -C 3
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ hg mv afile anotherfile
  $ hg commit -m "0.3m"

  $ hg debugrevlogindex -f 1 afile
     rev flag     size   link     p1     p2       nodeid
       0 0000        2      0     -1     -1 362fef284ce2
       1 0000        4      1      0     -1 125144f7e028
       2 0000        6      2      1     -1 4c982badb186
       3 0000        8      3      2     -1 19b1fc555737

  $ hg debugindex adifferentfile
     rev linkrev nodeid       p1           p2
       0       7 2565f3199a74 000000000000 000000000000

  $ hg debugindex anotherfile
     rev linkrev nodeid       p1           p2
       0       8 2565f3199a74 000000000000 000000000000

  $ hg debugindex fred
     rev linkrev nodeid       p1           p2
       0       6 12ab3bcc5ea4 000000000000 000000000000

  $ hg debugindex --manifest
     rev linkrev nodeid       p1           p2
       0       0 43eadb1d2d06 000000000000 000000000000
       1       1 8b89697eba2c 43eadb1d2d06 000000000000
       2       2 626a32663c2f 8b89697eba2c 000000000000
       3       3 f54c32f13478 626a32663c2f 000000000000
       4       6 de68e904d169 626a32663c2f 000000000000
       5       7 09bb521d218d de68e904d169 000000000000
       6       8 1fde233dfb0f f54c32f13478 000000000000

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 9 changesets with 7 changes to 4 files

  $ cd ..

  $ for i in 0 1 2 3 4 5 6 7 8; do
  >   echo
  >   echo ---- hg clone -r "$i" test test-"$i"
  >   hg clone -r "$i" test test-"$i"
  >   cd test-"$i"
  >   hg verify
  >   cd ..
  > done
  
  ---- hg clone -r 0 test test-0
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets f9ee2f85a263
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files
  
  ---- hg clone -r 1 test test-1
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets f9ee2f85a263:34c2bf6b0626
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 2 changes to 1 files
  
  ---- hg clone -r 2 test test-2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  new changesets f9ee2f85a263:e38ba6f5b7e0
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 3 changes to 1 files
  
  ---- hg clone -r 3 test test-3
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files
  new changesets f9ee2f85a263:eebf5a27f8ca
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 4 changesets with 4 changes to 1 files
  
  ---- hg clone -r 4 test test-4
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets f9ee2f85a263:095197eb4973
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 2 changes to 1 files
  
  ---- hg clone -r 5 test test-5
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  new changesets f9ee2f85a263:1bb50a9436a7
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 3 changesets with 3 changes to 1 files
  
  ---- hg clone -r 6 test test-6
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 5 changes to 2 files
  new changesets f9ee2f85a263:7373c1169842
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 4 changesets with 5 changes to 2 files
  
  ---- hg clone -r 7 test test-7
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 6 changes to 3 files
  new changesets f9ee2f85a263:a6a34bfa0076
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 5 changesets with 6 changes to 3 files
  
  ---- hg clone -r 8 test test-8
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 2 files
  new changesets f9ee2f85a263:aa35859c02ea
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 5 changesets with 5 changes to 2 files

  $ cd test-8
  $ hg pull ../test-7
  pulling from ../test-7
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 2 changes to 3 files (+1 heads)
  new changesets 095197eb4973:a6a34bfa0076
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 9 changesets with 7 changes to 4 files
  $ cd ..

  $ hg clone test test-9
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd test-9
  $ hg branch foobar
  marked working directory as branch foobar
  (branches are permanent and global, did you want a bookmark?)
  $ echo file2 >> file2
  $ hg add file2
  $ hg commit -m "changeset9"
  $ echo file3 >> file3
  $ hg add file3
  $ hg commit -m "changeset10"
  $ cd ..
  $ hg clone -r 9 -u foobar test-9 test-10
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 6 changes to 3 files
  new changesets f9ee2f85a263:7100abb79635
  updating to branch foobar
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved