Mercurial > hg
view tests/test-manifestv2.t @ 27475:a2e2a8fa5fd1
revlog: avoid string slice when decompressing u* chunks
Revlog chunks can be stored uncompressed. If the first byte of the
raw data is \0, we store the data as is. Else we prefix it with 'u'.
Before, we performed a string slice to strip out the 'u' prefix.
With this patch, we use a buffer to avoid an extra memory copy and
associated garbage collection overhead.
I was unable to verify any performance impact of this patch. For both
mozilla-central and the hg repos, the number of manifest revisions
with 'u' prefixes is very small - under 1%. So this change likely
isn't called enough to have an impact on manifest reading. However,
the reasoning behind this change is solid, so it should be safe.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 20 Dec 2015 16:00:27 -0800 |
parents | 2329ca3ebc7a |
children | eb586ed5d8ce |
line wrap: on
line source
Create repo with old manifest $ cat << EOF >> $HGRCPATH > [format] > usegeneraldelta=yes > EOF $ hg init existing $ cd existing $ echo footext > foo $ hg add foo $ hg commit -m initial We're using v1, so no manifestv2 entry is in requires yet. $ grep manifestv2 .hg/requires [1] Let's clone this with manifestv2 enabled to switch to the new format for future commits. $ cd .. $ hg clone --pull existing new --config experimental.manifestv2=1 requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd new Check that entry was added to .hg/requires. $ grep manifestv2 .hg/requires manifestv2 Make a new commit. $ echo newfootext > foo $ hg commit -m new Check that the manifest actually switched to v2. $ hg debugdata -m 0 foo\x0021e958b1dca695a60ee2e9cf151753204ee0f9e9 (esc) $ hg debugdata -m 1 \x00 (esc) \x00foo\x00 (esc) I\xab\x7f\xb8(\x83\xcas\x15\x9d\xc2\xd3\xd3:5\x08\xbad5_ (esc) Check that manifestv2 is used if the requirement is present, even if it's disabled in the config. $ echo newerfootext > foo $ hg --config experimental.manifestv2=False commit -m newer $ hg debugdata -m 2 \x00 (esc) \x00foo\x00 (esc) \xa6\xb1\xfb\xef]\x91\xa1\x19`\xf3.#\x90S\xf8\x06 \xe2\x19\x00 (esc) Check that we can still read v1 manifests. $ hg files -r 0 foo $ cd .. Check that entry is added to .hg/requires on repo creation $ hg --config experimental.manifestv2=True init repo $ cd repo $ grep manifestv2 .hg/requires manifestv2 Set up simple repo $ echo a > file1 $ echo b > file2 $ echo c > file3 $ hg ci -Aqm 'initial' $ echo d > file2 $ hg ci -m 'modify file2' Check that 'hg verify', which uses manifest.readdelta(), works $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 3 files, 2 changesets, 4 total revisions Check that manifest revlog is smaller than for v1 $ hg debugindex -m rev offset length delta linkrev nodeid p1 p2 0 0 81 -1 0 57361477c778 000000000000 000000000000 1 81 33 0 1 aeaab5a2ef74 57361477c778 000000000000