Mercurial > hg
view tests/test-histedit-drop.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 | a79776f427b4 |
children | 358c23e8f1c6 |
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$ . "$TESTDIR/histedit-helpers.sh" $ cat >> $HGRCPATH <<EOF > [extensions] > graphlog= > histedit= > EOF $ EDITED="$TESTTMP/editedhistory" $ cat > $EDITED <<EOF > drop 177f92b77385 c > pick e860deea161a e > pick 652413bf663e f > pick 055a42cdd887 d > EOF $ initrepo () > { > hg init r > cd r > for x in a b c d e f ; do > echo $x > $x > hg add $x > hg ci -m $x > done > } $ initrepo log before edit $ hg log --graph @ changeset: 5:652413bf663e | tag: tip | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: f | o changeset: 4:e860deea161a | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: e | o changeset: 3:055a42cdd887 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: d | o changeset: 2:177f92b77385 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: c | o changeset: 1:d2ae7f538514 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: b | o changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a edit the history $ HGEDITOR="cat \"$EDITED\" > " hg histedit 177f92b77385 2>&1 | fixbundle 0 files updated, 0 files merged, 4 files removed, 0 files unresolved 0 files updated, 0 files merged, 0 files removed, 0 files unresolved 0 files updated, 0 files merged, 0 files removed, 0 files unresolved 0 files updated, 0 files merged, 0 files removed, 0 files unresolved log after edit $ hg log --graph @ changeset: 4:708943196e52 | tag: tip | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: d | o changeset: 3:75cbdffecadb | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: f | o changeset: 2:493dc0964412 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: e | o changeset: 1:d2ae7f538514 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: b | o changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a manifest after edit $ hg manifest a b d e f $ cd ..