comparison mercurial/upgrade.py @ 31896:127b41e975fd

upgrade: split finding deficiencies from finding optimisations

Our ultimate goal is to make it easier to get a diagnostic of the repository
format. A first important and step for that is to separate part related to
repository format from the optimisation. We start by having two different
functions returning the two categories of possible "improvement".

31895:783b4c9bd5f5

        self.upgrademessage = upgrademessage

        for k, v in kwargs.items():
            setattr(self, k, v)

def findimprovements(repo):
    """Determine improvements that can be made to the repo during upgrade.

    Returns a list of ``upgradeimprovement`` describing repository deficiencies
    and optimizations.
    """
    newreporeqs = localrepo.newreporequirements(repo)

    improvements = []

    # We could detect lack of revlogv1 and store here, but they were added
    # in 0.9.2 and we don't support upgrading repos without these
    # requirements, so let's not bother.

    if 'fncache' not in repo.requirements:
        improvements.append(improvement(
            name='fncache',
            type=deficiency,
            description=_('long and reserved filenames may not work correctly; '
                          'repository performance is sub-optimal'),
            upgrademessage=_('repository will be more resilient to storing '

                             'operations should be improved'),
            fromdefault=True,
            fromconfig='fncache' in newreporeqs))

    if 'dotencode' not in repo.requirements:
        improvements.append(improvement(
            name='dotencode',
            type=deficiency,
            description=_('storage of filenames beginning with a period or '
                          'space may not work correctly'),
            upgrademessage=_('repository will be better able to store files '
                             'beginning with a space or period'),
            fromdefault=True,
            fromconfig='dotencode' in newreporeqs))

    if 'generaldelta' not in repo.requirements:
        improvements.append(improvement(
            name='generaldelta',
            type=deficiency,
            description=_('deltas within internal storage are unable to '
                          'choose optimal revisions; repository is larger and '
                          'slower than it could be; interaction with other '

    # changelogs with deltas.
    cl = repo.changelog
    for rev in cl:
        chainbase = cl.chainbase(rev)
        if chainbase != rev:
            improvements.append(improvement(
                name='removecldeltachain',
                type=deficiency,
                description=_('changelog storage is using deltas instead of '
                              'raw entries; changelog reading and any '
                              'operation relying on changelog data are slower '

                                 'faster; changelog size may be reduced'),
                fromdefault=True,
                fromconfig=True))
            break

    # Now for the optimizations.

    # These are unconditionally added. There is logic later that figures out
    # which ones to apply.

    improvements.append(improvement(
        name='redeltaparent',
        type=optimisation,
        description=_('deltas within internal storage will be recalculated to '
                      'choose an optimal base revision where this was not '
                      'already done; the size of the repository may shrink and '

                      'execution considerably; subsequent invocations should '
                      'not run noticeably slower'),
        upgrademessage=_('deltas within internal storage will choose a new '
                         'base revision if needed')))

    improvements.append(improvement(
        name='redeltamultibase',
        type=optimisation,
        description=_('deltas within internal storage will be recalculated '
                      'against multiple base revision and the smallest '
                      'difference will be used; the size of the repository may '

        upgrademessage=_('deltas within internal storage will choose an '
                         'optimal delta by computing deltas against multiple '
                         'parents; may slow down execution time '
                         'significantly')))

    improvements.append(improvement(
        name='redeltaall',
        type=optimisation,
        description=_('deltas within internal storage will always be '
                      'recalculated without reusing prior deltas; this will '
                      'likely make execution run several times slower; this '
                      'optimization is typically not needed'),
        upgrademessage=_('deltas within internal storage will be fully '
                         'recomputed; this will likely drastically slow down '
                         'execution time')))

    return improvements

def determineactions(repo, improvements, sourcereqs, destreqs,
                            optimize):
    """Determine upgrade actions that will be performed.

    Given a list of improvements as returned by ``upgradefindimprovements``,
    determine the list of upgrade actions that will be performed.

    The role of this function is to filter improvements if needed, apply
    recommended optimizations from the improvements list that make sense,
    etc.

        raise error.Abort(_('cannot upgrade repository; do not support '
                            'destination requirement: %s') %
                          _(', ').join(sorted(unsupportedreqs)))

    # Find and validate all improvements that can be made.
    improvements = findimprovements(repo)
    for i in improvements:
        if i.type not in (deficiency, optimisation):
            raise error.Abort(_('unexpected improvement type %s for %s') % (
                i.type, i.name))

31896:127b41e975fd

        self.upgrademessage = upgrademessage

        for k, v in kwargs.items():
            setattr(self, k, v)

def finddeficiencies(repo):
    """returns a list of deficiencies that the repo suffer from"""
    newreporeqs = localrepo.newreporequirements(repo)

    deficiencies = []

    # We could detect lack of revlogv1 and store here, but they were added
    # in 0.9.2 and we don't support upgrading repos without these
    # requirements, so let's not bother.

    if 'fncache' not in repo.requirements:
        deficiencies.append(improvement(
            name='fncache',
            type=deficiency,
            description=_('long and reserved filenames may not work correctly; '
                          'repository performance is sub-optimal'),
            upgrademessage=_('repository will be more resilient to storing '

                             'operations should be improved'),
            fromdefault=True,
            fromconfig='fncache' in newreporeqs))

    if 'dotencode' not in repo.requirements:
        deficiencies.append(improvement(
            name='dotencode',
            type=deficiency,
            description=_('storage of filenames beginning with a period or '
                          'space may not work correctly'),
            upgrademessage=_('repository will be better able to store files '
                             'beginning with a space or period'),
            fromdefault=True,
            fromconfig='dotencode' in newreporeqs))

    if 'generaldelta' not in repo.requirements:
        deficiencies.append(improvement(
            name='generaldelta',
            type=deficiency,
            description=_('deltas within internal storage are unable to '
                          'choose optimal revisions; repository is larger and '
                          'slower than it could be; interaction with other '

    # changelogs with deltas.
    cl = repo.changelog
    for rev in cl:
        chainbase = cl.chainbase(rev)
        if chainbase != rev:
            deficiencies.append(improvement(
                name='removecldeltachain',
                type=deficiency,
                description=_('changelog storage is using deltas instead of '
                              'raw entries; changelog reading and any '
                              'operation relying on changelog data are slower '

                                 'faster; changelog size may be reduced'),
                fromdefault=True,
                fromconfig=True))
            break

    return deficiencies

def findoptimizations(repo):
    """Determine optimisation that could be used during upgrade"""
    # These are unconditionally added. There is logic later that figures out
    # which ones to apply.
    optimizations = []

    optimizations.append(improvement(
        name='redeltaparent',
        type=optimisation,
        description=_('deltas within internal storage will be recalculated to '
                      'choose an optimal base revision where this was not '
                      'already done; the size of the repository may shrink and '

                      'execution considerably; subsequent invocations should '
                      'not run noticeably slower'),
        upgrademessage=_('deltas within internal storage will choose a new '
                         'base revision if needed')))

    optimizations.append(improvement(
        name='redeltamultibase',
        type=optimisation,
        description=_('deltas within internal storage will be recalculated '
                      'against multiple base revision and the smallest '
                      'difference will be used; the size of the repository may '

        upgrademessage=_('deltas within internal storage will choose an '
                         'optimal delta by computing deltas against multiple '
                         'parents; may slow down execution time '
                         'significantly')))

    optimizations.append(improvement(
        name='redeltaall',
        type=optimisation,
        description=_('deltas within internal storage will always be '
                      'recalculated without reusing prior deltas; this will '
                      'likely make execution run several times slower; this '
                      'optimization is typically not needed'),
        upgrademessage=_('deltas within internal storage will be fully '
                         'recomputed; this will likely drastically slow down '
                         'execution time')))

    return optimizations

def determineactions(repo, improvements, sourcereqs, destreqs,
                            optimize):
    """Determine upgrade actions that will be performed.

    Given a list of improvements as returned by ``finddeficiencies`` and
    ``findoptimizations``, determine the list of upgrade actions that
    will be performed.

    The role of this function is to filter improvements if needed, apply
    recommended optimizations from the improvements list that make sense,
    etc.

        raise error.Abort(_('cannot upgrade repository; do not support '
                            'destination requirement: %s') %
                          _(', ').join(sorted(unsupportedreqs)))

    # Find and validate all improvements that can be made.
    improvements = finddeficiencies(repo) + findoptimizations(repo)
    for i in improvements:
        if i.type not in (deficiency, optimisation):
            raise error.Abort(_('unexpected improvement type %s for %s') % (
                i.type, i.name))