Mercurial > hg
view relnotes/5.5 @ 51108:0250e45040f1
revlog: add a small cache of unfiltered chunk
This can provides a massive boost to the reading of multiple revision and the
computation of a valid delta chain.
This greatly help operation like `hg log --patch`, delta computation (helping
pull/unbundle), linkrev adjustment (helping copy tracing).
A first round of benchmark for `hg log --patch --limit 1000` shows improvement
in the 10-20% range on "small" repository like pypy or mercurial and large
improvements (about 33%) for more complex ones like netbeans and mozilla's.
These speeds up are consistent with the improvement to `hg pull` (from a server
sending poor deltas) I saw benchmarking this last year. Further benchmark will
be run during the freeze.
I added some configuration in the experimental space to be able to further test
the effect of various tuning for now. This feature should fit well in the
"usage/resource profile" configuration that we should land next cycle.
When it does not provides a benefit the overhead of the cache seem to be around
2%, a small price for the big improvement. In addition I believe we could shave
most of this overhead with a more efficent lru implementation.
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Fri, 27 Oct 2023 08:54:41 +0200 |
parents | 53a6febafc66 |
children |
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== New Features == * clonebundles can be annotated with the expected memory requirements using the `REQUIREDRAM` option. This allows clients to skip bundles created with large zstd windows and fallback to larger, but less demanding bundles. * The `phabricator` extension now provides more functionality of the arcanist CLI like changing the status of a differential. * Phases processing is much faster, especially for repositories with old non-public changesets. == New Experimental Features == * The core of some hg operations have been (and are being) implemented in rust, for speed. `hg status` on a repository with 300k tracked files goes from 1.8s to 0.6s for instance. This has currently been tested only on linux, and does not build on windows. See rust/README.rst in the mercurial repository for instructions to opt into this. * An experimental config `rewrite.empty-successor` was introduced to control what happens when rewrite operations result in empty changesets. == Bug Fixes == * For the case when connected to a TTY, stdout was fixed to be line-buffered on Python 3 (where it was block-buffered before, causing the process to seem hanging) and Windows on Python 2 (where it was unbuffered before). * Subversion sources of the convert extension were fixed to work on Python 3. * Subversion sources of the convert extension now interpret the encoding of URLs like Subversion. Previously, there were situations where the convert extension recognized a repository as present but Subversion did not, and vice versa. * The empty changeset check of in-memory rebases was fixed to match that of normal rebases (and that of the commit command). * The push command now checks the correct set of outgoing changesets for obsolete and unstable changesets. Previously, it could happen that the check prevented pushing changesets which were already on the server. == Backwards Compatibility Changes == * Mercurial now requires at least Python 2.7.9 or a Python version that backported modern SSL/TLS features (as defined in PEP 466), and that Python was compiled against a OpenSSL version supporting TLS 1.1 or TLS 1.2 (likely this requires the OpenSSL version to be at least 1.0.1). * The `hg perfwrite` command from contrib/perf.py was made more flexible and changed its default behavior. To get the previous behavior, run `hg perfwrite --nlines=100000 --nitems=1 --item='Testing write performance' --batch-line`. * The absorb extension now preserves changesets with no file changes that can be created by the commit command (those which change the branch name compared to the parent and those closing a branch head). == Internal API Changes == * logcmdutil.diffordiffstat() now takes contexts instead of nodes. * The `mergestate` class along with some related methods and constants have moved from `mercurial.merge` to a new `mercurial.mergestate` module. * The `phasecache` class now uses sparse dictionaries for the phase data. New accessors are provided to detect if any non-public changeset exists (`hasnonpublicphases`) and get the correponsponding root set (`nonpublicphaseroots`). * The `stdin`, `stdout` and `stderr` attributes of the `mercurial.pycompat` module were removed. Instead, the attributes of same name from the `mercurial.utils.procutil` module should be used, which provide more consistent behavior across Python versions and platforms.