Mercurial > hg
view tests/test-rebase-bookmarks.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 | 2944a6d35158 |
children | 2a1fac3650a5 |
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$ cat >> $HGRCPATH <<EOF > [extensions] > graphlog= > rebase= > > [phases] > publish=False > > [alias] > tglog = log -G --template "{rev}: '{desc}' bookmarks: {bookmarks}\n" > EOF Create a repo with several bookmarks $ hg init a $ cd a $ echo a > a $ hg ci -Am A adding a $ echo b > b $ hg ci -Am B adding b $ hg book 'X' $ hg book 'Y' $ echo c > c $ hg ci -Am C adding c $ hg book 'Z' $ hg up -q 0 $ echo d > d $ hg ci -Am D adding d created new head $ hg book W $ hg tglog @ 3: 'D' bookmarks: W | | o 2: 'C' bookmarks: Y Z | | | o 1: 'B' bookmarks: X |/ o 0: 'A' bookmarks: Move only rebased bookmarks $ cd .. $ hg clone -q a a1 $ cd a1 $ hg up -q Z $ hg rebase -s Y -d 3 saved backup bundle to $TESTTMP/a1/.hg/strip-backup/*-backup.hg (glob) $ hg tglog @ 3: 'C' bookmarks: Y Z | o 2: 'D' bookmarks: W | | o 1: 'B' bookmarks: X |/ o 0: 'A' bookmarks: Keep bookmarks to the correct rebased changeset $ cd .. $ hg clone -q a a2 $ cd a2 $ hg up -q Z $ hg rebase -s 1 -d 3 saved backup bundle to $TESTTMP/a2/.hg/strip-backup/*-backup.hg (glob) $ hg tglog @ 3: 'C' bookmarks: Y Z | o 2: 'B' bookmarks: X | o 1: 'D' bookmarks: W | o 0: 'A' bookmarks: Keep active bookmark on the correct changeset $ cd .. $ hg clone -q a a3 $ cd a3 $ hg up -q X $ hg rebase -d W saved backup bundle to $TESTTMP/a3/.hg/strip-backup/*-backup.hg (glob) $ hg tglog @ 3: 'C' bookmarks: Y Z | o 2: 'B' bookmarks: X | o 1: 'D' bookmarks: W | o 0: 'A' bookmarks: $ cd ..