Mercurial > hg
view tests/test-merge-revert2.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 | 2371f4aea665 |
children | 25d5a9ecbb85 |
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$ hg init $ echo "added file1" > file1 $ echo "another line of text" >> file1 $ echo "added file2" > file2 $ hg add file1 file2 $ hg commit -m "added file1 and file2" $ echo "changed file1" >> file1 $ hg commit -m "changed file1" $ hg -q log 1:dfab7f3c2efb 0:c3fa057dd86f $ hg id dfab7f3c2efb tip $ hg update -C 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg id c3fa057dd86f $ echo "changed file1" >> file1 $ hg id c3fa057dd86f+ $ hg revert --no-backup --all reverting file1 $ hg diff $ hg status $ hg id c3fa057dd86f $ hg update 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg diff $ hg status $ hg id dfab7f3c2efb tip $ hg update -C 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo "changed file1 different" >> file1 $ hg update merging file1 warning: conflicts during merge. merging file1 incomplete! (edit conflicts, then use 'hg resolve --mark') 0 files updated, 0 files merged, 0 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges [1] $ hg diff --nodates diff -r dfab7f3c2efb file1 --- a/file1 +++ b/file1 @@ -1,3 +1,7 @@ added file1 another line of text +<<<<<<< local +changed file1 different +======= changed file1 +>>>>>>> other $ hg status M file1 ? file1.orig $ hg id dfab7f3c2efb+ tip $ hg revert --no-backup --all reverting file1 $ hg diff $ hg status ? file1.orig $ hg id dfab7f3c2efb tip $ hg revert -r tip --no-backup --all $ hg diff $ hg status ? file1.orig $ hg id dfab7f3c2efb tip $ hg update -C 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg diff $ hg status ? file1.orig $ hg id dfab7f3c2efb tip