Mercurial > hg
view tests/test-committer.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 | 6409a5c75125 |
children | 625533523c9e |
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$ unset HGUSER $ EMAIL="My Name <myname@example.com>" $ export EMAIL $ hg init test $ cd test $ touch asdf $ hg add asdf $ hg commit -m commit-1 $ hg tip changeset: 0:53f268a58230 tag: tip user: My Name <myname@example.com> date: Thu Jan 01 00:00:00 1970 +0000 summary: commit-1 $ unset EMAIL $ echo 1234 > asdf $ hg commit -u "foo@bar.com" -m commit-1 $ hg tip changeset: 1:3871b2a9e9bf tag: tip user: foo@bar.com date: Thu Jan 01 00:00:00 1970 +0000 summary: commit-1 $ echo "[ui]" >> .hg/hgrc $ echo "username = foobar <foo@bar.com>" >> .hg/hgrc $ echo 12 > asdf $ hg commit -m commit-1 $ hg tip changeset: 2:8eeac6695c1c tag: tip user: foobar <foo@bar.com> date: Thu Jan 01 00:00:00 1970 +0000 summary: commit-1 $ echo 1 > asdf $ hg commit -u "foo@bar.com" -m commit-1 $ hg tip changeset: 3:957606a725e4 tag: tip user: foo@bar.com date: Thu Jan 01 00:00:00 1970 +0000 summary: commit-1 $ echo 123 > asdf $ echo "[ui]" > .hg/hgrc $ echo "username = " >> .hg/hgrc $ hg commit -m commit-1 abort: no username supplied (see "hg help config") [255] $ rm .hg/hgrc $ hg commit -m commit-1 2>&1 no username found, using '[^']*' instead (re) $ echo space > asdf $ hg commit -u ' ' -m commit-1 transaction abort! rollback completed abort: empty username! [255] $ cd ..