Mercurial > hg
view tests/test-issue1306.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 | 41885892796e |
children | 2fc86d92c4a9 |
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http://mercurial.selenic.com/bts/issue1306 Initialize remote repo with branches: $ hg init remote $ cd remote $ echo a > a $ hg ci -Ama adding a $ hg branch br marked working directory as branch br (branches are permanent and global, did you want a bookmark?) $ hg ci -Amb $ echo c > c $ hg ci -Amc adding c $ hg log changeset: 2:ae3d9c30ec50 branch: br tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: c changeset: 1:3f7f930ca414 branch: br user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a $ cd .. Try cloning -r branch: $ hg clone -rbr remote local1 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files updating to branch br 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local1 parents changeset: 2:ae3d9c30ec50 branch: br tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: c Try cloning -rother clone#branch: $ hg clone -r0 remote#br local2 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local2 parents changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a Try cloning -r1 clone#branch: $ hg clone -r1 remote#br local3 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files updating to branch br 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local3 parents changeset: 1:3f7f930ca414 branch: br user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b