Mercurial > hg
view tests/test-convert-hg-sink.t @ 17970:0b03454abae7
ancestor: faster algorithm for difference of ancestor sets
One of the major reasons rebase is slow in large repositories is
the computation of the detach set: the set of ancestors of the
changesets to rebase not in the destination parent. This is currently
done via a revset that does two walks all the way to the root of
the DAG. Instead of doing that, to find ancestors of a set <revs>
not in another set <common> we walk up the tree in reverse revision
number order, maintaining sets of nodes visited from <revs>, <common>
or both.
For the common case where the sets are close both topologically and
in revision number (relative to repository size), this has been
found to speed up rebase by around 15-20%. When the nodes are farther
apart and the DAG is highly branching, it is harder to say which
would win.
Here's how long computing the detach set takes in a linear repository
with over 400000 changesets, rebasing near tip:
Rebasing across 4 changesets
Revset method: 2.2s
New algorithm: 0.00015s
Rebasing across 250 changesets
Revset method: 2.2s
New algorithm: 0.00069s
Rebasing across 10000 changesets
Revset method: 2.4s
New algorithm: 0.019s
author | Siddharth Agarwal <sid0@fb.com> |
---|---|
date | Mon, 26 Nov 2012 11:46:51 -0800 |
parents | 81bf25ddd76a |
children | 77872b002e73 |
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$ cat >> $HGRCPATH <<EOF > [extensions] > convert= > [convert] > hg.saverev=False > EOF $ hg init orig $ cd orig $ echo foo > foo $ echo bar > bar $ hg ci -qAm 'add foo and bar' $ hg rm foo $ hg ci -m 'remove foo' $ mkdir foo $ echo file > foo/file $ hg ci -qAm 'add foo/file' $ hg tag some-tag $ hg log changeset: 3:593cbf6fb2b4 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Added tag some-tag for changeset ad681a868e44 changeset: 2:ad681a868e44 tag: some-tag user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo/file changeset: 1:cbba8ecc03b7 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: remove foo changeset: 0:327daa9251fa user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo and bar $ cd .. $ hg convert orig new 2>&1 | grep -v 'subversion python bindings could not be loaded' initializing destination new repository scanning source... sorting... converting... 3 add foo and bar 2 remove foo 1 add foo/file 0 Added tag some-tag for changeset ad681a868e44 $ cd new $ hg out ../orig comparing with ../orig searching for changes no changes found [1] dirstate should be empty: $ hg debugstate $ hg parents -q $ hg up -C 3 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg copy bar baz put something in the dirstate: $ hg debugstate > debugstate $ grep baz debugstate a 0 -1 unset baz copy: bar -> baz add a new revision in the original repo $ cd ../orig $ echo baz > baz $ hg ci -qAm 'add baz' $ cd .. $ hg convert orig new 2>&1 | grep -v 'subversion python bindings could not be loaded' scanning source... sorting... converting... 0 add baz $ cd new $ hg out ../orig comparing with ../orig searching for changes no changes found [1] dirstate should be the same (no output below): $ hg debugstate > new-debugstate $ diff debugstate new-debugstate no copies $ hg up -C 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg debugrename baz baz not renamed $ cd .. test tag rewriting $ cat > filemap <<EOF > exclude foo > EOF $ hg convert --filemap filemap orig new-filemap 2>&1 | grep -v 'subversion python bindings could not be loaded' initializing destination new-filemap repository scanning source... sorting... converting... 4 add foo and bar 3 remove foo 2 add foo/file 1 Added tag some-tag for changeset ad681a868e44 0 add baz $ cd new-filemap $ hg tags tip 2:6f4fd1df87fb some-tag 0:ba8636729451 $ cd ..