Mercurial > hg
view tests/test-clone-pull-corruption.t @ 47120:7109a38830c9
dirstate-tree: Fold "tracked descendants" counter update in main walk
For the purpose of implementing `has_tracked_dir` (which means "has tracked
descendants) without an expensive sub-tree traversal, we maintaing a counter
of tracked descendants on each "directory" node of the tree-shaped dirstate.
Before this changeset, mutating or inserting a node at a given path would
involve:
* Walking the tree from root through ancestors to find the node or the spot
where to insert it
* Looking at the previous node if any to decide what counter update is needed
* Performing any node mutation
* Walking the tree *again* to update counters in ancestor nodes
When profiling `hg status` on a large repo, this second walk takes times
while loading a the dirstate from disk.
It turns out we have enough information to decide before he first tree walk
what counter update is needed. This changeset merges the two walks, gaining
~10% of the total time for `hg update` (in the same hyperfine benchmark as
the previous changeset).
---
Profiling was done by compiling with this `.cargo/config`:
[profile.release]
debug = true
then running with:
py-spy record -r 500 -n -o /tmp/hg.json --format speedscope -- \
./hg status -R $REPO --config experimental.dirstate-tree.in-memory=1
then visualizing the recorded JSON file in https://www.speedscope.app/
Differential Revision: https://phab.mercurial-scm.org/D10554
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Fri, 30 Apr 2021 14:22:14 +0200 |
parents | f1186c292d03 |
children | 2f2682f40ea0 |
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Corrupt an hg repo with a pull started during an aborted commit Create two repos, so that one of them can pull from the other one. $ hg init source $ cd source $ touch foo $ hg add foo $ hg ci -m 'add foo' $ hg clone . ../corrupted updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo >> foo $ hg ci -m 'change foo' Add a hook to wait 5 seconds and then abort the commit $ cd ../corrupted $ echo "[hooks]" >> .hg/hgrc $ echo 'pretxncommit = sh -c "sleep 5; exit 1"' >> .hg/hgrc start a commit... $ touch bar $ hg add bar $ hg ci -m 'add bar' & ... and start a pull while the commit is still running $ sleep 1 $ hg pull ../source 2>/dev/null pulling from ../source transaction abort! rollback completed abort: pretxncommit hook exited with status 1 searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files new changesets 52998019f625 (run 'hg update' to get a working copy) see what happened $ wait $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 2 changesets with 2 changes to 1 files $ cd ..