Mercurial > hg
view tests/test-debugbundle.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 | 4ab66de46a96 |
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Create a test repository: $ hg init repo $ cd repo $ touch a ; hg add a ; hg ci -ma $ touch b ; hg add b ; hg ci -mb $ touch c ; hg add c ; hg ci -mc $ hg bundle --base 0 --rev tip bundle.hg 2 changesets found Terse output: $ hg debugbundle bundle.hg 0e067c57feba1a5694ca4844f05588bb1bf82342 991a3460af53952d10ec8a295d3d2cc2e5fa9690 Verbose output: $ hg debugbundle --all bundle.hg format: id, p1, p2, cset, delta base, len(delta) changelog 0e067c57feba1a5694ca4844f05588bb1bf82342 3903775176ed42b1458a6281db4a0ccf4d9f287a 0000000000000000000000000000000000000000 0e067c57feba1a5694ca4844f05588bb1bf82342 3903775176ed42b1458a6281db4a0ccf4d9f287a 80 991a3460af53952d10ec8a295d3d2cc2e5fa9690 0e067c57feba1a5694ca4844f05588bb1bf82342 0000000000000000000000000000000000000000 991a3460af53952d10ec8a295d3d2cc2e5fa9690 0e067c57feba1a5694ca4844f05588bb1bf82342 80 manifest 686dbf0aeca417636fa26a9121c681eabbb15a20 8515d4bfda768e04af4c13a69a72e28c7effbea7 0000000000000000000000000000000000000000 0e067c57feba1a5694ca4844f05588bb1bf82342 8515d4bfda768e04af4c13a69a72e28c7effbea7 55 ae25a31b30b3490a981e7b96a3238cc69583fda1 686dbf0aeca417636fa26a9121c681eabbb15a20 0000000000000000000000000000000000000000 991a3460af53952d10ec8a295d3d2cc2e5fa9690 686dbf0aeca417636fa26a9121c681eabbb15a20 55 b b80de5d138758541c5f05265ad144ab9fa86d1db 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 0e067c57feba1a5694ca4844f05588bb1bf82342 0000000000000000000000000000000000000000 12 c b80de5d138758541c5f05265ad144ab9fa86d1db 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 991a3460af53952d10ec8a295d3d2cc2e5fa9690 0000000000000000000000000000000000000000 12 $ cd ..