##// END OF EJS Templates
deltas: set estimated compression upper bound to "3x" instead of "10x"...
deltas: set estimated compression upper bound to "3x" instead of "10x" In pratice, we very rarely observer compression better than "3x" on manifest deltas. Having a more aggressive estimate significantly helps our pathological use case on a private repository. Here are a comparison of timings using different upper bound. Estimated compression | ø | ×10 | ×5 | ×3 | timing | 14.11 | 2.61 | 1.96 | 1.53 | We also tested the impact of this series on an array of public repositories. This shown no impact in either size nor timing. Full data set below for those interested. Size ---- Regarding size, not significant impact have been noticed on neither public nor private repositories. Here are the number we gathered on public repositories: zlib/upperbound | no | 10x | 5x | 3x mercurial | 5 875 730 | 5 875 730 | 5 875 730 | 5 875 730 pypy | 27 782 913 | 27 782 913 | 27 782 913 | 27 782 913 netbeans | 159 161 207 | 159 161 207 | 159 161 207 | 159 959 879 (+0.5%) mozilla-central | 323 841 642 | 323 841 642 | 323 841 642 | 319 867 519 (-2.5%) mozilla-try | 746 649 123 | 746 649 123 | 746 649 123 | 741 155 568 (-0.7%) private-repo | 1 485 287 294 | 1 485 287 294 | 1 485 287 294 | 1 409 248 382 (-5.1%) zstd/upperbound | no | 10x | 5x | 3x mercurial | 5 895 206 | 5 895 206 | 5 895 206 | 5 895 206 pypy | 28 689 230 | 28 689 230 | 28 689 230 | 28 689 230 netbeans | 157 636 387 | 157 636 387 | 157 636 387 | 159 692 678 (+1.3%) mozilla-central | 317 650 281 | 317 650 281 | 317 650 281 | 319 613 603 (+0.6%) mozilla-try | 737 555 275 | 737 555 275 | 737 555 275 | 738 079 473 (+0.1%) private-repo | 1 352 362 982 | 1 352 362 982 | 1 346 961 880 | 1 361 327 384 (+0.7%) Speed ------ Timing gathered using `hg perfrevlogwrite -m`. Value are in seconds. mercurial zlib | no | 10x | 5x | 3x | total | 65.551783 | 65.388887 | 65.260658 | 65.321199 | max | 0.034544 | 0.034571 | 0.034659 | 0.034521 | 99.99% | 0.034544 | 0.034571 | 0.034659 | 0.034521 | zstd | no | 10x | 5x | 3x | total | 49.118449 | 49.054062 | 48.753588 | 48.740230 | max | 0.009338 | 0.009239 | 0.009202 | 0.009178 | 99.99% | 0.007618 | 0.007639 | 0.007626 | 0.007621 | pypy zlib | no | 10x | 5x | 3x | total | 560.865984 | 558.983817 | 559.083815 | 559.349152 | max | 0.219614 | 0.215922 | 0.218112 | 0.218107 | 99.99% | 0.219614 | 0.215922 | 0.218112 | 0.218107 | zstd | no | 10x | 5x | 3x | total | 349.393280 | 347.395819 | 347.185407 | 345.643985 | max | 0.084143 | 0.083536 | 0.081834 | 0.082178 | 99.99% | 0.039445 | 0.039639 | 0.039612 | 0.039175 | netbeans zlib | no | 10x | 5x | 3x | total | 33103.327727 | 33314.932260 | 33211.745233 | 33345.891778 | max | 2.666852 | 2.672059 | 2.662453 | 2.662936 | 99.99% | 2.058772 | 2.070429 | 2.069569 | 2.064653 | zstd | no | 10x | 5x | 3x | total | 20112.102708 | 20095.879719 | 20083.390300 | 20123.221859 | max | 2.063482 | 2.062851 | 2.065229 | 2.060147 | 99.99% | 1.146647 | 1.143794 | 1.142933 | 1.146529 | mozilla zlib | no | 10x | 5x | 3x | total | 41374.102138 | 41418.816773 | 41381.956370 | 41334.280732 | max | 3.383474 | 3.387400 | 3.405711 | 3.387316 | 99.99% | 1.006755 | 1.005954 | 1.007700 | 1.007373 | zstd | no | 10x | 5x | 3x | total | 24689.691520 | 24643.939662 | 24664.630027 | 24664.512714 | max | 1.460822 | 1.449640 | 1.439747 | 1.465304 | 99.99% | 0.527111 | 0.527377 | 0.527807 | 0.527226 |

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state.py
87 lines | 2.8 KiB | text/x-python | PythonLexer
# state.py - writing and reading state files in Mercurial
#
# Copyright 2018 Pulkit Goyal <pulkitmgoyal@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""
This file contains class to wrap the state for commands and other
related logic.
All the data related to the command state is stored as dictionary in the object.
The class has methods using which the data can be stored to disk in a file under
.hg/ directory.
We store the data on disk in cbor, for which we use the CBOR format to encode
the data.
"""
from __future__ import absolute_import
from . import (
error,
util,
)
from .utils import (
cborutil,
)
class cmdstate(object):
"""a wrapper class to store the state of commands like `rebase`, `graft`,
`histedit`, `shelve` etc. Extensions can also use this to write state files.
All the data for the state is stored in the form of key-value pairs in a
dictionary.
The class object can write all the data to a file in .hg/ directory and
can populate the object data reading that file.
Uses cbor to serialize and deserialize data while writing and reading from
disk.
"""
def __init__(self, repo, fname):
""" repo is the repo object
fname is the file name in which data should be stored in .hg directory
"""
self._repo = repo
self.fname = fname
def read(self):
"""read the existing state file and return a dict of data stored"""
return self._read()
def save(self, version, data):
"""write all the state data stored to .hg/<filename> file
we use third-party library cbor to serialize data to write in the file.
"""
if not isinstance(version, int):
raise error.ProgrammingError("version of state file should be"
" an integer")
with self._repo.vfs(self.fname, 'wb', atomictemp=True) as fp:
fp.write('%d\n' % version)
for chunk in cborutil.streamencode(data):
fp.write(chunk)
def _read(self):
"""reads the state file and returns a dictionary which contain
data in the same format as it was before storing"""
with self._repo.vfs(self.fname, 'rb') as fp:
try:
int(fp.readline())
except ValueError:
raise error.CorruptedState("unknown version of state file"
" found")
return cborutil.decodeall(fp.read())[0]
def delete(self):
"""drop the state file if exists"""
util.unlinkpath(self._repo.vfs.join(self.fname), ignoremissing=True)
def exists(self):
"""check whether the state file exists or not"""
return self._repo.vfs.exists(self.fname)