Summary:
Now that all our repos are treemanifest, let's enable the extension by
default in tests. Once we're certain no one needs it in production we'll also
make it the default in core Mercurial.
This diff includes a minor fix in treemanifest to be aware of always-enabled
extensions. It won't matter until we actually add treemanifest to the list of
default enabled extensions, but I caught this while testing things.
Reviewed By: ikostia
Differential Revision: D15030253
fbshipit-source-id: d8361f915928b6ad90665e6ed330c1df5c8d8d86
Summary:
Move the strip extension to core. Rename the command to `hg debugstrip` as it
is not intended for use by users. Users should use `hg hide` instead.
Reviewed By: quark-zju
Differential Revision: D14185822
fbshipit-source-id: ef096488cb94b72a7bb79f5bf153c064e0555b34
Summary:
When running with a Python runtime with a slightly different zlib module,
some `zlib.compress` outputs are different. Some tests are testing the
length, or the content of `zlib.compress` output, directly or indirectly.
That's causing issues.
This patch adds a `common-zlib` hghave test so it can be used to gate tests
checking zlib output. Some lengths are also changed to glob patterns to be
compatible.
Reviewed By: ryanmce
Differential Revision: D6937735
fbshipit-source-id: 2328a39d7f2022f16d51f61b6178568b26dfe2fb
Summary:
The isgooddelta tweak was introduced in D2693043 (perftweaks: change revlog
delta heuristic, 2015-11-24). Comparing with the existing version, the only
change is that we removed `dist > maxdist` check.
Note that the upstream commit 895ecec31 (revlog: add an experimental option
to mitigated delta issues (issue5480), 2017-06-23) also introduces a config
option to override `maxdist` to make the condition fail, which basically does
a same thing.
Instead of introducing new config options or adding more "if"s to the
codebase to make it more obscure, let's just simplify it by disabling the
check entirely, and removing the `dist` concept, removing two config
options: `experimental.maxdeltachainspan` and `perftweaks.preferdeltas`.
The `chainlen > self._maxchainlen` check should be enough for keeping
delta chain length bounded.
Reviewed By: DurhamG
Differential Revision: D6752529
fbshipit-source-id: e8fd8ec39240191db5fb274190fc661e97087a78
# skip-blame because this was mechanically rewritten the following script. I
ran it on both *.t and *.py, but none of the *.py changes were proper. All *.t
ones appear to be, and they run without addition failures on both Windows and
Linux.
import argparse
import os
import re
ap = argparse.ArgumentParser()
ap.add_argument('path', nargs='+')
opts = ap.parse_args()
globre = re.compile(r'^(.*) \(glob\)(.*)$')
for p in opts.path:
tmp = p + '.tmp'
with open(p, 'rb') as src, open(tmp, 'wb') as dst:
for line in src:
m = globre.match(line)
if not m or '$LOCALIP' in line or '*' in line:
dst.write(line)
continue
if '?' in line[:-3] or ('?' in line[:-3] and line[-3:] != '(?)'):
dst.write(line)
continue
dst.write(m.group(1) + m.group(2) + '\n')
os.unlink(p)
os.rename(tmp, p)
Upon pull or unbundle, we display a message with the range of new revisions
fetched. This revision range could readily be used after a pull to look out
what's new with 'hg log'. The algorithm takes care of filtering "obsolete"
revisions that might be present in transaction's "changes" but should not be
displayed to the end user.
The general delta heuristic to select a delta do not scale with the number of
branch. The delta base is frequently too far away to be able to reuse a chain
according to the "distance" criteria. This leads to insertion of larger delta (or
even full text) that themselves push the bases for the next delta further away
leading to more large deltas and full texts. This full text and frequent
recomputation throw Mercurial performance in disarray.
For example of a slightly large repository
280 000 files (2 150 000 versions)
430 000 changesets (10 000 topological heads)
Number below compares repository with and without the distance criteria:
manifest size:
with: 21.4 GB
without: 0.3 GB
store size:
with: 28.7 GB
without 7.4 GB
bundle last 15 00 revisions:
with: 800 seconds
971 MB
without: 50 seconds
73 MB
unbundle time (of the last 15K revisions):
with: 1150 seconds (~19 minutes)
without: 35 seconds
Similar issues has been observed in other repositories.
Adding a new option or "feature" on stable is uncommon. However, given that this
issues is making Mercurial practically unusable, I'm exceptionally targeting
this patch for stable.
What is actually needed is a full rework of the delta building and reading
logic. However, that will be a longer process and churn not suitable for stable.
In the meantime, we introduces a quick and dirty mitigation of this in the
'experimental' config space. The new option introduces a way to set the maximum
amount of memory usable to store a diff in memory. This extend the ability for
Mercurial to create chains without removing all safe guard regarding memory
access. The option should be phased out when core has a more proper solution
available.
Setting the limit to '0' remove all limits, setting it to '-1' use the default
limit (textsize x 4).
Before this patch, unbundling a stripped changeset would make it a
draft (unless the parent was secret). This meant that one would lose
phase information when stripping and unbundling secret changesets. The
same thing was true for public changesets. While stripping public
changesets is generally rare, it's done frequently by e.g. the
narrowhg extension.
We also include the phases in the temporary bundle, just in case
stripping were to fail after that point, so the user can still restore
the repo including phase information. Before this patch, the phases
were left untouched during the bundling and unbundling of the
temporary bundle. Only at the end of the transaction would
phasecache.filterunknown() be called to remove phase roots that were
no longer valid. We now need to call that also after the first
stripping, i.e. before applying the temporary bundle. Otherwise
unbundling the temporary bundle will cause a read of the phase cache
which has stripped changesets in the cache and that fails.
Like with obsmarkers, we unconditionally include the phases in the
bundle when stripping (when using bundle2, such as when generaldelta
is enabled). The reason for doing that for strip but not for bundle is
that strip bundles are not meant to be shared outside the repo, so we
don't care as much about compatibility.
The bundle2 changegroup part has an advisory param saying how many
changesets are in the part. Before this patch, we were setting
this part when generating bundle2 parts via the wire protocol but
not when generating local bundle2 files.
A side effect of not setting the changeset count part is that progress
bars don't work when applying changesets. As the tests show, this
impacted clone bundles, shelve, backup bundles, `hg unbundle`, and
anything touching bundle2 files.
This patch adds a backdoor to allow us to pass state from
changegroup generation into the unbundler. We store the number
of changesets in the changegroup in this state and use it to
populate the aforementioned advisory part parameter when generating
the bundle2 bundle.
I concede that I'm not thrilled by how state is being passed in
changegroup.py (it feels a bit hacky). I would love to overhaul the
rather confusing set of functions in changegroup.py with something that
passes rich objects around instead of e.g. low-level generators.
However, given the code freeze for 3.9 is imminent, I'd rather not
undertake this endeavor right now. This feels like the easiest way
to get the parameter added to the changegroup part.
`hg debugbundle` is calling repr() on bundle2 part params, which are
now util.sortdict instances. Unfortunately, repr() doesn't appear
to be deterministic for util.sortdict. So, we implement one.
We include the type name because that's the common convention for
__repr__ implementations. Having the type name in `hg debugbundle`
is a bit ugly. But it's a debug command and I don't care enough to
fix it.
This patch includes addition of absolute_import and print_function to the
files where they are missing. The modern importing conventions are also followed.
In the most complex case, we try using the incoming delta base, then
we try both parents, and then we try the previous revlog entry. If
none of these result in a good delta, we natually use the null
revision as base. However, we sometimes consider the nullrev before we
have exhausted our other options. Specifically, when both parents are
null, we use the nullrev as delta base if it produces a good delta
(according to _isgooddelta()), and we fail to try the previous revlog
entry as delta base. After e60126c6093d (addrevision: use general
delta when the incoming base delta is bad, 2015-12-01), it can also
happen for non-merge commits when the incoming delta is not good.
The Firefox repo (from many months back) shrinks a tiny bit with this
patch: from 1.855GB to 1.830GB (1.4%). The hg repo itself shrinks even
less: by less than 0.1%. There may be repos that get larger instead.
This undoes the unexplained test change in e60126c6093d.
We unify the delta selection process to be a simple three options process:
- try to use the incoming delta (if lazydeltabase is on)
- try to find a suitable parents to delta against (if gd is on)
- try to delta against the tipmost revision
The first of this option that yield a valid delta will be used.
The test change in 'test-generaldelta.t' show this behavior as we use a delta
against the parent instead of a full delta when the incoming delta is not
suitable.
This as some impact on 'test-bundle.t' because a delta somewhere changes. It
does not seems to change the test semantic and have been ignored.
The currently used manifest is too small and cannot sustain a chain length
above "1". This make testing the 'lazybasedelta' behavior hard. So we add an
extra file in the manifest to help testing in the next changeset.
The semantic of existing tests have been checked and is not changed.
This test check the difference between various configurations we have to pin the
type of some repositories to ensure the test is still correct when we change the
default.
This option will make repositories created as general delta by default but will
not make Mercurial aggressively recompute deltas for all incoming bundle.
Instead, the delta contained in the bundle will be used. This will allow us to
start having general delta repositories created everywhere without triggering
massive recomputation costs for all new clients cloning from old servers.
The bundle10 format (plain changegroup-01) does not support general delta and
result into expensive delta re-computation when stripping. If the repository is
general delta, we store backups as bundle20 containing a changegroup-02 payload.
We remove the experimental feature related to strip backup bundle format because
this achieve the same goal in a leaner way. Removing the experimental option is
fine, that is why it experimental in the first place.
Compression of these bundles are coming in later changesets.
This adds an option for delta'ing against both p1 and p2 when applying merge
revisions and picking whichever is smallest.
Some before and after stats on manifest.d size:
internal large repo:
before: 1.2 GB
after: 930 MB
mozilla-central:
before: 261 MB
after: 92 MB
Previously, if reorder was true during the creation of a changegroup bundle,
it was possible that the manifest and filelogs would be reordered such that the
resulting bundle filelog had a linkrev that pointed to a commit that was not
the earliest instance of the filelog revision. For example:
With commits:
0<-1<---3<-4
\ /
--2<---
if 2 and 3 added the same version of a file, if the manifests of 2 and 3 have
their order reversed, but the changelog did not, it could produce a filelog with
linkrevs 0<-3 instead of 0<-2, which meant if commit 3 was stripped, it would
delete that file data from the repository and commit 2 would be corrupt (as
would any future pulls that tried to build upon that version of the file).
The fix is to make the linkrev fixup smarter. Previously it considered the first
manifest that added a file to be the first commit that added that file, which is
not true. Now, for every file revision we add to the bundle we make sure we
attach it to the earliest applicable linkrev.
Previously basecache was incorrectly initialized before adding the first
revision from a changegroup. Basecache value influences when full revisions are
stored in revlog (when using generaldelta). As a result it was possible to
generate a generaldelta-revlog that could be bigger by arbitrary factor than its
non-generaldelta equivalent.
