Mercurial > hg
view tests/test-merge10.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 | f2719b387380 |
children | eb586ed5d8ce |
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Test for changeset 9fe267f77f56ff127cf7e65dc15dd9de71ce8ceb (merge correctly when all the files in a directory are moved but then local changes are added in the same directory) $ hg init a $ cd a $ mkdir -p testdir $ echo a > testdir/a $ hg add testdir/a $ hg commit -m a $ cd .. $ hg clone a b updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd a $ echo alpha > testdir/a $ hg commit -m remote-change $ cd .. $ cd b $ mkdir testdir/subdir $ hg mv testdir/a testdir/subdir/a $ hg commit -m move $ mkdir newdir $ echo beta > newdir/beta $ hg add newdir/beta $ hg commit -m local-addition $ hg pull ../a pulling from ../a searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files (+1 heads) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg up -C 2 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge merging testdir/subdir/a and testdir/a to testdir/subdir/a 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg stat M testdir/subdir/a $ hg diff --nodates diff -r bc21c9773bfa testdir/subdir/a --- a/testdir/subdir/a +++ b/testdir/subdir/a @@ -1,1 +1,1 @@ -a +alpha $ cd ..