view hgext/show.py @ 39506:b66ea3fc3a86

sparse-revlog: set max delta chain length to on thousand The new snapshot system used in the sparse-revlog case gave us some small size benefit so far. However its most important property is to gracefully handle harder limit on delta chainlength. Long delta chain has a very detrimental impact on read (and write) performance in revlog. Being able to shorter them provide a great boost. However, shorting delta used to result significantly lower compression ratio. The intermediate snapshots effectively suppress most of this effect (even all in some case). # Effect on the test repository The repository we use for test is not "realistic" but can still show this in action using an unreasonably low chain limit. Limiting the chain length show a sizeable increase but stay under control: +6% for limit=15; +15% for limit=10. Without the snapshot system the increase is significantly bigger: +45% for limit=15; +80% for limit=10. Even slightly larger than without delta chain limit, the resulting size is still smaller than before we started doing snapshots. Here is a table for comparison. *Since the repository is not branchy, the initial sparse-revlog version does not bring much benefit compare to the non-sparse one): chain length limit | none | limit=15 | limit=10 | without sparse-revlog | 62 818 987 | 112 664 615 | 131 222 574 | without snapshot | 74 365 490 | 108 211 410 | 133 857 764 | with snapshot | 59 230 936 | 63 002 924 | 68 415 329 | # Effect On Real Life Repositories The series provides significant benefits on all kind of repositories. Using `hg debugupgraderepo -o redeltaparent --run`, we recomputed delta chain for various repositories with different settings: - delta chain length: unlimited or 1000 limit - sparse-revlog: enabled or disabled - this series: applied or not applied We can observe multiple types of effect: - On very branchy repositories: * The delta chain limit as low impact on the repo size. * Intermediate snapshot greatly reduces manifest size: - pypy: -80% - netbeans: -95% * The delta chain limit is effective, without a size impact: - netbeans average: 613 -> 282 - private #1 average: 1 068 -> 307 - On more linear repository: * Intermediate snapshot limit the impact of delta chain limit: - mozilla: without the series: +360% with the series: +25% * The delta chain limit provides large improvement: - mozilla's average chain length: unlimited: 15 338 limited: 469 * Despite the chain length limit, the manifest size is reduced: - mercurial: -25% - mozilla: -30% It is clear that the use of chains of intermediate snapshots provide large benefits both in storage size and delta chains quality. We should now switch our effort toward making sure the write performance are acceptable. Then, `sparse-revlog` will be a suitable format for all new repository. # Raw Statistic * no-sparse: general delta repository not using sparse-revlog * no-snapshot: sparse-revlog repository not using this series * snapshot: sparse-revlog repository using this series mercurial Manifest Size: limit | none | 1000 ------------|-------------|------------ no-sparse | 8 021 373 | 8 199 366 no-snapshot | 8 103 561 | 8 259 719 snapshot | 6 137 116 | 6 126 433 Manifest Chain length data limit || none || 1000 || value || average | max || average | max || ------------||---------|---------||---------|---------|| no-sparse || 307 | 1456 || 279 | 1000 || no-snapshot || 312 | 1456 || 283 | 1000 || snapshot || 248 | 1208 || 241 | 1000 || Full Store Size limit | none | 1000 ------------|-------------|------------ no-sparse | 51 013 198 | 51 201 574 no-snapshot | 50 930 795 | 51 141 006 snapshot | 48 072 037 | 48 093 572 pypy Manifest Size: limit | none | 1000 ------------|-------------|------------ no-sparse | 193 987 784 | 193 987 784 no-snapshot | 163 171 745 | 163 312 229 snapshot | 34 605 900 | 34 600 750 Manifest Chain length data limit || none || 1000 || value || average | max || average | max || ------------||---------|---------||---------|---------|| no-sparse || 101 | 692 || 101 | 692 || no-snapshot || 151 | 1307 || 148 | 1000 || snapshot || 128 | 1309 || 125 | 1000 || Full Store Size limit | none | 1000 ------------|-------------|------------ no-sparse | 495 931 473 | 495 931 473 no-snapshot | 465 441 017 | 465 581 501 snapshot | 355 467 301 | 355 472 451 Mozilla Manifest Size: limit | none | 1000 ------------|----------------|--------------- no-sparse | 416 757 148 | 1 869 009 668 no-snapshot | 401 592 370 | 1 843 493 795 snapshot | 224 359 521 | 284 615 500 Manifest Chain length data limit || none || 1000 || value || average | max || average | max || ------------||---------|---------||---------|---------|| no-sparse || 15 333 | 58 980 || 468 | 1 000 || no-snapshot || 15 336 | 58 980 || 469 | 1 000 || snapshot || 15 338 | 58 983 || 469 | 1 000 || Full Store Size limit | none | 1000 ------------|----------------|--------------- no-sparse | 2 712 477 887 | 4 164 995 451 no-snapshot | 2 698 887 835 | 4 141 054 304 snapshot | 2 518 130 385 | 2 578 587 596 Netbeans Manifest Size: limit | none | 1000 ------------|----------------|--------------- no-sparse | 4 766 794 101 | 4 870 642 687 no-snapshot | 4 334 806 082 | 4 428 681 309 snapshot | 232 659 666 | 240 330 665 Manifest Chain length data limit || none || 1000 || value || average | max || average | max || ------------||---------|---------||---------|---------|| no-sparse || 597 | 6802 || 254 | 1 000 || no-snapshot || 648 | 6 802 || 305 | 1 000 || snapshot || 613 | 6 804 || 282 | 1 000 || Full Store Size limit | none | 1000 ------------|----------------|--------------- no-sparse | 5 807 347 998 | 5 911 196 584 no-snapshot | 5 375 398 602 | 5 469 273 829 snapshot | 1 282 519 928 | 1 290 190 927 Private repo #1 Manifest Size: limit | none | 1000 ------------|-----------------|--------------- no-sparse | 41 389 010 840 | 41 398 162 091 no-snapshot | 9 737 319 435 | 10 223 773 150 snapshot | 744 215 807 | 747 961 822 Manifest Chain length data limit || none || 1000 || value || average | max || average | max || ------------||---------|---------||---------|---------|| no-sparse || 245 | 8 885 || 81 | 1 000 || no-snapshot || 1 225 | 8 885 || 336 | 1 000 || snapshot || 1 068 | 7 909 || 307 | 1 000 || Full Store Size limit | none | 1000 ------------|----------------|--------------- no-sparse | 49 646 065 126 | 49 655 216 377 no-snapshot | 17 924 862 856 | 18 411 316 571 snapshot | 9 009 024 710 | 9 012 770 725 Private repo #2 We currently have less data available for that repository. * Before is a sparse-revlog repository without this series * After is a sparse-revlog repository with this series + 1000 chain limit Manifest Size: Before: 1 531 485 040 bytes After: 1 091 422 451 bytes Manifest Chain: Before: 2 218 avg; 6 575 Max After: 442 avg; 1 000 Max Full Store Size Before: 15 203 955 615 after: 8 207 180 693
author Boris Feld <boris.feld@octobus.net>
date Fri, 07 Sep 2018 11:18:45 -0400
parents 7b2955624777
children c303d65d2e34
line wrap: on
line source

# show.py - Extension implementing `hg show`
#
# Copyright 2017 Gregory Szorc <gregory.szorc@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.

"""unified command to show various repository information (EXPERIMENTAL)

This extension provides the :hg:`show` command, which provides a central
command for displaying commonly-accessed repository data and views of that
data.

The following config options can influence operation.

``commands``
------------

``show.aliasprefix``
   List of strings that will register aliases for views. e.g. ``s`` will
   effectively set config options ``alias.s<view> = show <view>`` for all
   views. i.e. `hg swork` would execute `hg show work`.

   Aliases that would conflict with existing registrations will not be
   performed.
"""

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial.node import (
    nullrev,
)
from mercurial import (
    cmdutil,
    commands,
    destutil,
    error,
    formatter,
    graphmod,
    logcmdutil,
    phases,
    pycompat,
    registrar,
    revset,
    revsetlang,
    scmutil,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

cmdtable = {}
command = registrar.command(cmdtable)

revsetpredicate = registrar.revsetpredicate()

class showcmdfunc(registrar._funcregistrarbase):
    """Register a function to be invoked for an `hg show <thing>`."""

    # Used by _formatdoc().
    _docformat = '%s -- %s'

    def _extrasetup(self, name, func, fmtopic=None, csettopic=None):
        """Called with decorator arguments to register a show view.

        ``name`` is the sub-command name.

        ``func`` is the function being decorated.

        ``fmtopic`` is the topic in the style that will be rendered for
        this view.

        ``csettopic`` is the topic in the style to be used for a changeset
        printer.

        If ``fmtopic`` is specified, the view function will receive a
        formatter instance. If ``csettopic`` is specified, the view
        function will receive a changeset printer.
        """
        func._fmtopic = fmtopic
        func._csettopic = csettopic

showview = showcmdfunc()

@command('show', [
    # TODO: Switch this template flag to use cmdutil.formatteropts if
    # 'hg show' becomes stable before --template/-T is stable. For now,
    # we are putting it here without the '(EXPERIMENTAL)' flag because it
    # is an important part of the 'hg show' user experience and the entire
    # 'hg show' experience is experimental.
    ('T', 'template', '', ('display with template'), _('TEMPLATE')),
    ], _('VIEW'))
def show(ui, repo, view=None, template=None):
    """show various repository information

    A requested view of repository data is displayed.

    If no view is requested, the list of available views is shown and the
    command aborts.

    .. note::

       There are no backwards compatibility guarantees for the output of this
       command. Output may change in any future Mercurial release.

       Consumers wanting stable command output should specify a template via
       ``-T/--template``.

    List of available views:
    """
    if ui.plain() and not template:
        hint = _('invoke with -T/--template to control output format')
        raise error.Abort(_('must specify a template in plain mode'), hint=hint)

    views = showview._table

    if not view:
        ui.pager('show')
        # TODO consider using formatter here so available views can be
        # rendered to custom format.
        ui.write(_('available views:\n'))
        ui.write('\n')

        for name, func in sorted(views.items()):
            ui.write(('%s\n') % pycompat.sysbytes(func.__doc__))

        ui.write('\n')
        raise error.Abort(_('no view requested'),
                          hint=_('use "hg show VIEW" to choose a view'))

    # TODO use same logic as dispatch to perform prefix matching.
    if view not in views:
        raise error.Abort(_('unknown view: %s') % view,
                          hint=_('run "hg show" to see available views'))

    template = template or 'show'

    fn = views[view]
    ui.pager('show')

    if fn._fmtopic:
        fmtopic = 'show%s' % fn._fmtopic
        with ui.formatter(fmtopic, {'template': template}) as fm:
            return fn(ui, repo, fm)
    elif fn._csettopic:
        ref = 'show%s' % fn._csettopic
        spec = formatter.lookuptemplate(ui, ref, template)
        displayer = logcmdutil.changesettemplater(ui, repo, spec, buffered=True)
        return fn(ui, repo, displayer)
    else:
        return fn(ui, repo)

@showview('bookmarks', fmtopic='bookmarks')
def showbookmarks(ui, repo, fm):
    """bookmarks and their associated changeset"""
    marks = repo._bookmarks
    if not len(marks):
        # This is a bit hacky. Ideally, templates would have a way to
        # specify an empty output, but we shouldn't corrupt JSON while
        # waiting for this functionality.
        if not isinstance(fm, formatter.jsonformatter):
            ui.write(_('(no bookmarks set)\n'))
        return

    revs = [repo[node].rev() for node in marks.values()]
    active = repo._activebookmark
    longestname = max(len(b) for b in marks)
    nodelen = longestshortest(repo, revs)

    for bm, node in sorted(marks.items()):
        fm.startitem()
        fm.context(ctx=repo[node])
        fm.write('bookmark', '%s', bm)
        fm.write('node', fm.hexfunc(node), fm.hexfunc(node))
        fm.data(active=bm == active,
                longestbookmarklen=longestname,
                nodelen=nodelen)

@showview('stack', csettopic='stack')
def showstack(ui, repo, displayer):
    """current line of work"""
    wdirctx = repo['.']
    if wdirctx.rev() == nullrev:
        raise error.Abort(_('stack view only available when there is a '
                            'working directory'))

    if wdirctx.phase() == phases.public:
        ui.write(_('(empty stack; working directory parent is a published '
                   'changeset)\n'))
        return

    # TODO extract "find stack" into a function to facilitate
    # customization and reuse.

    baserev = destutil.stackbase(ui, repo)
    basectx = None

    if baserev is None:
        baserev = wdirctx.rev()
        stackrevs = {wdirctx.rev()}
    else:
        stackrevs = set(repo.revs('%d::.', baserev))

    ctx = repo[baserev]
    if ctx.p1().rev() != nullrev:
        basectx = ctx.p1()

    # And relevant descendants.
    branchpointattip = False
    cl = repo.changelog

    for rev in cl.descendants([wdirctx.rev()]):
        ctx = repo[rev]

        # Will only happen if . is public.
        if ctx.phase() == phases.public:
            break

        stackrevs.add(ctx.rev())

        # ctx.children() within a function iterating on descandants
        # potentially has severe performance concerns because revlog.children()
        # iterates over all revisions after ctx's node. However, the number of
        # draft changesets should be a reasonably small number. So even if
        # this is quadratic, the perf impact should be minimal.
        if len(ctx.children()) > 1:
            branchpointattip = True
            break

    stackrevs = list(sorted(stackrevs, reverse=True))

    # Find likely target heads for the current stack. These are likely
    # merge or rebase targets.
    if basectx:
        # TODO make this customizable?
        newheads = set(repo.revs('heads(%d::) - %ld - not public()',
                                 basectx.rev(), stackrevs))
    else:
        newheads = set()

    allrevs = set(stackrevs) | newheads | set([baserev])
    nodelen = longestshortest(repo, allrevs)

    try:
        cmdutil.findcmd('rebase', commands.table)
        haverebase = True
    except (error.AmbiguousCommand, error.UnknownCommand):
        haverebase = False

    # TODO use templating.
    # TODO consider using graphmod. But it may not be necessary given
    # our simplicity and the customizations required.
    # TODO use proper graph symbols from graphmod

    tres = formatter.templateresources(ui, repo)
    shortesttmpl = formatter.maketemplater(ui, '{shortest(node, %d)}' % nodelen,
                                           resources=tres)
    def shortest(ctx):
        return shortesttmpl.renderdefault({'ctx': ctx, 'node': ctx.hex()})

    # We write out new heads to aid in DAG awareness and to help with decision
    # making on how the stack should be reconciled with commits made since the
    # branch point.
    if newheads:
        # Calculate distance from base so we can render the count and so we can
        # sort display order by commit distance.
        revdistance = {}
        for head in newheads:
            # There is some redundancy in DAG traversal here and therefore
            # room to optimize.
            ancestors = cl.ancestors([head], stoprev=basectx.rev())
            revdistance[head] = len(list(ancestors))

        sourcectx = repo[stackrevs[-1]]

        sortedheads = sorted(newheads, key=lambda x: revdistance[x],
                             reverse=True)

        for i, rev in enumerate(sortedheads):
            ctx = repo[rev]

            if i:
                ui.write(': ')
            else:
                ui.write('  ')

            ui.write(('o  '))
            displayer.show(ctx, nodelen=nodelen)
            displayer.flush(ctx)
            ui.write('\n')

            if i:
                ui.write(':/')
            else:
                ui.write(' /')

            ui.write('    (')
            ui.write(_('%d commits ahead') % revdistance[rev],
                     label='stack.commitdistance')

            if haverebase:
                # TODO may be able to omit --source in some scenarios
                ui.write('; ')
                ui.write(('hg rebase --source %s --dest %s' % (
                         shortest(sourcectx), shortest(ctx))),
                         label='stack.rebasehint')

            ui.write(')\n')

        ui.write(':\n:    ')
        ui.write(_('(stack head)\n'), label='stack.label')

    if branchpointattip:
        ui.write(' \\ /  ')
        ui.write(_('(multiple children)\n'), label='stack.label')
        ui.write('  |\n')

    for rev in stackrevs:
        ctx = repo[rev]
        symbol = '@' if rev == wdirctx.rev() else 'o'

        if newheads:
            ui.write(': ')
        else:
            ui.write('  ')

        ui.write(symbol, '  ')
        displayer.show(ctx, nodelen=nodelen)
        displayer.flush(ctx)
        ui.write('\n')

    # TODO display histedit hint?

    if basectx:
        # Vertically and horizontally separate stack base from parent
        # to reinforce stack boundary.
        if newheads:
            ui.write(':/   ')
        else:
            ui.write(' /   ')

        ui.write(_('(stack base)'), '\n', label='stack.label')
        ui.write(('o  '))

        displayer.show(basectx, nodelen=nodelen)
        displayer.flush(basectx)
        ui.write('\n')

@revsetpredicate('_underway([commitage[, headage]])')
def underwayrevset(repo, subset, x):
    args = revset.getargsdict(x, 'underway', 'commitage headage')
    if 'commitage' not in args:
        args['commitage'] = None
    if 'headage' not in args:
        args['headage'] = None

    # We assume callers of this revset add a topographical sort on the
    # result. This means there is no benefit to making the revset lazy
    # since the topographical sort needs to consume all revs.
    #
    # With this in mind, we build up the set manually instead of constructing
    # a complex revset. This enables faster execution.

    # Mutable changesets (non-public) are the most important changesets
    # to return. ``not public()`` will also pull in obsolete changesets if
    # there is a non-obsolete changeset with obsolete ancestors. This is
    # why we exclude obsolete changesets from this query.
    rs = 'not public() and not obsolete()'
    rsargs = []
    if args['commitage']:
        rs += ' and date(%s)'
        rsargs.append(revsetlang.getstring(args['commitage'],
                                           _('commitage requires a string')))

    mutable = repo.revs(rs, *rsargs)
    relevant = revset.baseset(mutable)

    # Add parents of mutable changesets to provide context.
    relevant += repo.revs('parents(%ld)', mutable)

    # We also pull in (public) heads if they a) aren't closing a branch
    # b) are recent.
    rs = 'head() and not closed()'
    rsargs = []
    if args['headage']:
        rs += ' and date(%s)'
        rsargs.append(revsetlang.getstring(args['headage'],
                                           _('headage requires a string')))

    relevant += repo.revs(rs, *rsargs)

    # Add working directory parent.
    wdirrev = repo['.'].rev()
    if wdirrev != nullrev:
        relevant += revset.baseset({wdirrev})

    return subset & relevant

@showview('work', csettopic='work')
def showwork(ui, repo, displayer):
    """changesets that aren't finished"""
    # TODO support date-based limiting when calling revset.
    revs = repo.revs('sort(_underway(), topo)')
    nodelen = longestshortest(repo, revs)

    revdag = graphmod.dagwalker(repo, revs)

    ui.setconfig('experimental', 'graphshorten', True)
    logcmdutil.displaygraph(ui, repo, revdag, displayer, graphmod.asciiedges,
                            props={'nodelen': nodelen})

def extsetup(ui):
    # Alias `hg <prefix><view>` to `hg show <view>`.
    for prefix in ui.configlist('commands', 'show.aliasprefix'):
        for view in showview._table:
            name = '%s%s' % (prefix, view)

            choice, allcommands = cmdutil.findpossible(name, commands.table,
                                                       strict=True)

            # This alias is already a command name. Don't set it.
            if name in choice:
                continue

            # Same for aliases.
            if ui.config('alias', name, None):
                continue

            ui.setconfig('alias', name, 'show %s' % view, source='show')

def longestshortest(repo, revs, minlen=4):
    """Return the length of the longest shortest node to identify revisions.

    The result of this function can be used with the ``shortest()`` template
    function to ensure that a value is unique and unambiguous for a given
    set of nodes.

    The number of revisions in the repo is taken into account to prevent
    a numeric node prefix from conflicting with an integer revision number.
    If we fail to do this, a value of e.g. ``10023`` could mean either
    revision 10023 or node ``10023abc...``.
    """
    if not revs:
        return minlen
    cl = repo.changelog
    return max(len(scmutil.shortesthexnodeidprefix(repo, cl.node(r), minlen))
               for r in revs)

# Adjust the docstring of the show command so it shows all registered views.
# This is a bit hacky because it runs at the end of module load. When moved
# into core or when another extension wants to provide a view, we'll need
# to do this more robustly.
# TODO make this more robust.
def _updatedocstring():
    longest = max(map(len, showview._table.keys()))
    entries = []
    for key in sorted(showview._table.keys()):
        entries.append(pycompat.sysstr('    %s   %s' % (
            key.ljust(longest), showview._table[key]._origdoc)))

    cmdtable['show'][0].__doc__ = pycompat.sysstr('%s\n\n%s\n    ') % (
        cmdtable['show'][0].__doc__.rstrip(),
        pycompat.sysstr('\n\n').join(entries))

_updatedocstring()