Mercurial > hg
view tests/test-bheads.t @ 18040:fe8caf28d580
strip: make query to get new bookmark target cheaper
The current query to get the new bookmark target for stripped revisions
involves multiple walks up the DAG, and is really expensive, taking over 2.5
seconds on a repository with over 400,000 changesets even if just one
changeset is being stripped.
A slightly simplified version of the current query is
max(heads(::<tostrip> - <tostrip>))
We make two observations here.
1. For any set s, max(heads(s)) == max(s). That is because revision numbers
define a topological order, so that the element with the highest revision
number in s will not have any children in s.
2. For any set s, max(::s - s) == max(parents(s) - s). In other words, the
ancestor of s with the highest revision number not in s is a parent of one
of the revs in s. Why? Because if it were an ancestor but not a parent of s,
it would have a descendant that would be a parent of s. This descendant
would have a higher revision number, leading to a contradiction.
Combining these two observations, we rewrite the revset query as
max(parents(<tostrip>) - <tostrip>)
The time complexity is now linear in the number of changesets being stripped.
For the above repository, the query now takes 0.1 seconds when one changeset
is stripped. This speeds up operations that use repair.strip, like the rebase
and strip commands.
author | Siddharth Agarwal <sid0@fb.com> |
---|---|
date | Wed, 05 Dec 2012 14:33:15 -0800 |
parents | f2719b387380 |
children | 701df761aa94 |
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$ heads() > { > hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@" > } $ hg init a $ cd a $ echo 'root' >root $ hg add root $ hg commit -m "Adding root node" $ heads 0: Adding root node () ------- $ heads . 0: Adding root node () ======= $ echo 'a' >a $ hg add a $ hg branch a marked working directory as branch a (branches are permanent and global, did you want a bookmark?) $ hg commit -m "Adding a branch" $ heads 1: Adding a branch (a) 0: Adding root node () ------- $ heads . 1: Adding a branch (a) ======= $ hg update -C 0 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo 'b' >b $ hg add b $ hg branch b marked working directory as branch b (branches are permanent and global, did you want a bookmark?) $ hg commit -m "Adding b branch" $ heads 2: Adding b branch (b) 1: Adding a branch (a) 0: Adding root node () ------- $ heads . 2: Adding b branch (b) ======= $ echo 'bh1' >bh1 $ hg add bh1 $ hg commit -m "Adding b branch head 1" $ heads 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- $ heads . 3: Adding b branch head 1 (b) ======= $ hg update -C 2 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo 'bh2' >bh2 $ hg add bh2 $ hg commit -m "Adding b branch head 2" created new head $ heads 4: Adding b branch head 2 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () $ heads . 4: Adding b branch head 2 (b) 3: Adding b branch head 1 (b) ======= $ hg update -C 2 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo 'bh3' >bh3 $ hg add bh3 $ hg commit -m "Adding b branch head 3" created new head $ heads 5: Adding b branch head 3 (b) 4: Adding b branch head 2 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- $ heads . 5: Adding b branch head 3 (b) 4: Adding b branch head 2 (b) 3: Adding b branch head 1 (b) ======= $ hg merge 4 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg commit -m "Merging b branch head 2 and b branch head 3" $ heads 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- $ heads . 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ======= $ echo 'c' >c $ hg add c $ hg branch c marked working directory as branch c (branches are permanent and global, did you want a bookmark?) $ hg commit -m "Adding c branch" $ heads 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- $ heads . 7: Adding c branch (c) ======= $ heads -r 3 . no open branch heads found on branches c (started at 3) [1] $ heads -r 2 . 7: Adding c branch (c) ------- $ hg update -C 4 0 files updated, 0 files merged, 2 files removed, 0 files unresolved ------- $ heads -r 3 . 3: Adding b branch head 1 (b) ------- $ heads -r 2 . 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- $ heads -r 7 . no open branch heads found on branches b (started at 7) [1] ======= $ for i in 0 1 2 3 4 5 6 7; do > hg update -C "$i" > heads > echo '-------' > heads . > echo '-------' > done 0 files updated, 0 files merged, 2 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 0: Adding root node () ------- 1 files updated, 0 files merged, 0 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 1: Adding a branch (a) ------- 1 files updated, 0 files merged, 1 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- 1 files updated, 0 files merged, 0 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- 1 files updated, 0 files merged, 1 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- 1 files updated, 0 files merged, 1 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- 1 files updated, 0 files merged, 0 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- 1 files updated, 0 files merged, 0 files removed, 0 files unresolved 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () ------- 7: Adding c branch (c) ------- ======= $ for i in a b c z; do > heads "$i" > echo '-------' > done 1: Adding a branch (a) ------- 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) ------- 7: Adding c branch (c) ------- abort: unknown revision 'z'! ------- ======= $ heads 0 1 2 3 4 5 6 7 7: Adding c branch (c) 6: Merging b branch head 2 and b branch head 3 (b) 3: Adding b branch head 1 (b) 1: Adding a branch (a) 0: Adding root node () Topological heads: $ heads -t 7: Adding c branch (c) 3: Adding b branch head 1 (b) 1: Adding a branch (a) $ cd .. ______________ "created new head" message tests $ hg init newheadmsg $ cd newheadmsg Init: no msg $ echo 1 > a $ hg ci -Am "a0: Initial root" adding a $ echo 2 >> a $ hg ci -m "a1 (HN)" $ hg branch b marked working directory as branch b (branches are permanent and global, did you want a bookmark?) $ echo 1 > b $ hg ci -Am "b2: Initial root for branch b" adding b $ echo 2 >> b $ hg ci -m "b3 (HN)" Case NN: msg $ hg up -q null $ hg branch -f b marked working directory as branch b (branches are permanent and global, did you want a bookmark?) $ echo 1 > bb $ hg ci -Am "b4 (NN): new topo root for branch b" adding bb created new head Case HN: no msg $ echo 2 >> bb $ hg ci -m "b5 (HN)" Case BN: msg $ hg branch -f default marked working directory as branch default (branches are permanent and global, did you want a bookmark?) $ echo 1 > aa $ hg ci -Am "a6 (BN): new branch root" adding aa created new head Case CN: msg $ hg up -q 4 $ echo 3 >> bbb $ hg ci -Am "b7 (CN): regular new head" adding bbb created new head Case BB: msg $ hg up -q 4 $ hg merge -q 3 $ hg branch -f default marked working directory as branch default (branches are permanent and global, did you want a bookmark?) $ hg ci -m "a8 (BB): weird new branch root" created new head Case CB: msg $ hg up -q 4 $ hg merge -q 1 $ hg ci -m "b9 (CB): new head from branch merge" created new head Case HB: no msg $ hg up -q 7 $ hg merge -q 6 $ hg ci -m "b10 (HB): continuing head from branch merge" Case CC: msg $ hg up -q 4 $ hg merge -q 2 $ hg ci -m "b11 (CC): new head from merge" created new head Case CH: no msg $ hg up -q 2 $ hg merge -q 10 $ hg ci -m "b12 (CH): continuing head from merge" Case HH: no msg $ hg merge -q 3 $ hg ci -m "b12 (HH): merging two heads" $ cd ..