view mercurial/bundlerepo.py @ 35116:da91e7309daf

bundle2: don't use seekable bundle2 parts by default (issue5691) The last commit removed the last use of the bundle2 part seek() API in the generic bundle2 part iteration code. This means we can now switch to using unseekable bundle2 parts by default and have the special consumers that actually need the behavior request it. This commit changes unbundle20.iterparts() to expose non-seekable unbundlepart instances by default. If seekable parts are needed, callers can pass "seekable=True." The bundlerepo class needs seekable parts, so it does this. The interrupt handler is also changed to use a regular unbundlepart. So, by default, all consumers except bundlerepo will see unseekable parts. Because the behavior of the iterparts() benchmark changed, we add a variation to test seekable parts vs unseekable parts. And because parts no longer have seek() unless "seekable=True," we update the "part seek" benchmark. Speaking of benchmarks, this change has the following impact to `hg perfbundleread` on an uncompressed bundle of the Firefox repo (6,070,036,163 bytes): ! read(8k) ! wall 0.722709 comb 0.720000 user 0.150000 sys 0.570000 (best of 14) ! read(16k) ! wall 0.602208 comb 0.590000 user 0.080000 sys 0.510000 (best of 17) ! read(32k) ! wall 0.554018 comb 0.560000 user 0.050000 sys 0.510000 (best of 18) ! read(128k) ! wall 0.520086 comb 0.530000 user 0.020000 sys 0.510000 (best of 20) ! bundle2 forwardchunks() ! wall 2.996329 comb 3.000000 user 2.300000 sys 0.700000 (best of 4) ! bundle2 iterparts() ! wall 8.070791 comb 8.060000 user 7.180000 sys 0.880000 (best of 3) ! wall 6.983756 comb 6.980000 user 6.220000 sys 0.760000 (best of 3) ! bundle2 iterparts() seekable ! wall 8.132131 comb 8.110000 user 7.160000 sys 0.950000 (best of 3) ! bundle2 part seek() ! wall 10.370142 comb 10.350000 user 7.430000 sys 2.920000 (best of 3) ! wall 10.860942 comb 10.840000 user 7.790000 sys 3.050000 (best of 3) ! bundle2 part read(8k) ! wall 8.599892 comb 8.580000 user 7.720000 sys 0.860000 (best of 3) ! wall 7.258035 comb 7.260000 user 6.470000 sys 0.790000 (best of 3) ! bundle2 part read(16k) ! wall 8.265361 comb 8.250000 user 7.360000 sys 0.890000 (best of 3) ! wall 7.099891 comb 7.080000 user 6.310000 sys 0.770000 (best of 3) ! bundle2 part read(32k) ! wall 8.290308 comb 8.280000 user 7.330000 sys 0.950000 (best of 3) ! wall 6.964685 comb 6.950000 user 6.130000 sys 0.820000 (best of 3) ! bundle2 part read(128k) ! wall 8.204900 comb 8.150000 user 7.210000 sys 0.940000 (best of 3) ! wall 6.852867 comb 6.850000 user 6.060000 sys 0.790000 (best of 3) The significant speedup is due to not incurring the overhead to track payload offset data. Of course, this overhead is proportional to bundle2 part size. So a multiple gigabyte changegroup part is on the extreme side of the spectrum for real-world impact. In addition to the CPU efficiency wins, not tracking offset data also means not using memory to hold that data. Using a bundle based on the example BSD repository in issue 5691, this change has a drastic impact to memory usage during `hg unbundle` (`hg clone` would behave similarly). Before, memory usage incrementally increased for the duration of bundle processing. In other words, as we advanced through the changegroup and bundle2 part, we kept allocating more memory to hold offset data. After this change, we still increase memory during changegroup application. But the rate of increase is significantly slower. (A bulk of the remaining gradual increase appears to be the storing of revlog sizes in the transaction object to facilitate rollback.) The RSS at the end of filelog application is as follows: Before: ~752 MB After: ~567 MB So, we were storing ~185 MB of offset data that we never even used. Talk about wasteful! .. api:: bundle2 parts are no longer seekable by default. .. perf:: bundle2 read I/O throughput significantly increased. .. perf:: Significant memory use reductions when reading from bundle2 bundles. On the BSD repository, peak RSS during changegroup application decreased by ~185 MB from ~752 MB to ~567 MB. Differential Revision: https://phab.mercurial-scm.org/D1390
author Gregory Szorc <gregory.szorc@gmail.com>
date Mon, 13 Nov 2017 21:10:37 -0800
parents 2b72bc88043f
children b1c9853e0775
line wrap: on
line source

# bundlerepo.py - repository class for viewing uncompressed bundles
#
# Copyright 2006, 2007 Benoit Boissinot <bboissin@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.

"""Repository class for viewing uncompressed bundles.

This provides a read-only repository interface to bundles as if they
were part of the actual repository.
"""

from __future__ import absolute_import

import os
import shutil
import tempfile

from .i18n import _
from .node import nullid

from . import (
    bundle2,
    changegroup,
    changelog,
    cmdutil,
    discovery,
    error,
    exchange,
    filelog,
    localrepo,
    manifest,
    mdiff,
    node as nodemod,
    pathutil,
    phases,
    pycompat,
    revlog,
    util,
    vfs as vfsmod,
)

class bundlerevlog(revlog.revlog):
    def __init__(self, opener, indexfile, cgunpacker, linkmapper):
        # How it works:
        # To retrieve a revision, we need to know the offset of the revision in
        # the bundle (an unbundle object). We store this offset in the index
        # (start). The base of the delta is stored in the base field.
        #
        # To differentiate a rev in the bundle from a rev in the revlog, we
        # check revision against repotiprev.
        opener = vfsmod.readonlyvfs(opener)
        revlog.revlog.__init__(self, opener, indexfile)
        self.bundle = cgunpacker
        n = len(self)
        self.repotiprev = n - 1
        self.bundlerevs = set() # used by 'bundle()' revset expression
        for deltadata in cgunpacker.deltaiter():
            node, p1, p2, cs, deltabase, delta, flags = deltadata

            size = len(delta)
            start = cgunpacker.tell() - size

            link = linkmapper(cs)
            if node in self.nodemap:
                # this can happen if two branches make the same change
                self.bundlerevs.add(self.nodemap[node])
                continue

            for p in (p1, p2):
                if p not in self.nodemap:
                    raise error.LookupError(p, self.indexfile,
                                            _("unknown parent"))

            if deltabase not in self.nodemap:
                raise LookupError(deltabase, self.indexfile,
                                  _('unknown delta base'))

            baserev = self.rev(deltabase)
            # start, size, full unc. size, base (unused), link, p1, p2, node
            e = (revlog.offset_type(start, flags), size, -1, baserev, link,
                 self.rev(p1), self.rev(p2), node)
            self.index.insert(-1, e)
            self.nodemap[node] = n
            self.bundlerevs.add(n)
            n += 1

    def _chunk(self, rev, df=None):
        # Warning: in case of bundle, the diff is against what we stored as
        # delta base, not against rev - 1
        # XXX: could use some caching
        if rev <= self.repotiprev:
            return revlog.revlog._chunk(self, rev)
        self.bundle.seek(self.start(rev))
        return self.bundle.read(self.length(rev))

    def revdiff(self, rev1, rev2):
        """return or calculate a delta between two revisions"""
        if rev1 > self.repotiprev and rev2 > self.repotiprev:
            # hot path for bundle
            revb = self.index[rev2][3]
            if revb == rev1:
                return self._chunk(rev2)
        elif rev1 <= self.repotiprev and rev2 <= self.repotiprev:
            return revlog.revlog.revdiff(self, rev1, rev2)

        return mdiff.textdiff(self.revision(rev1, raw=True),
                              self.revision(rev2, raw=True))

    def revision(self, nodeorrev, _df=None, raw=False):
        """return an uncompressed revision of a given node or revision
        number.
        """
        if isinstance(nodeorrev, int):
            rev = nodeorrev
            node = self.node(rev)
        else:
            node = nodeorrev
            rev = self.rev(node)

        if node == nullid:
            return ""

        rawtext = None
        chain = []
        iterrev = rev
        # reconstruct the revision if it is from a changegroup
        while iterrev > self.repotiprev:
            if self._cache and self._cache[1] == iterrev:
                rawtext = self._cache[2]
                break
            chain.append(iterrev)
            iterrev = self.index[iterrev][3]
        if rawtext is None:
            rawtext = self.baserevision(iterrev)

        while chain:
            delta = self._chunk(chain.pop())
            rawtext = mdiff.patches(rawtext, [delta])

        text, validatehash = self._processflags(rawtext, self.flags(rev),
                                                'read', raw=raw)
        if validatehash:
            self.checkhash(text, node, rev=rev)
        self._cache = (node, rev, rawtext)
        return text

    def baserevision(self, nodeorrev):
        # Revlog subclasses may override 'revision' method to modify format of
        # content retrieved from revlog. To use bundlerevlog with such class one
        # needs to override 'baserevision' and make more specific call here.
        return revlog.revlog.revision(self, nodeorrev, raw=True)

    def addrevision(self, *args, **kwargs):
        raise NotImplementedError

    def addgroup(self, *args, **kwargs):
        raise NotImplementedError

    def strip(self, *args, **kwargs):
        raise NotImplementedError

    def checksize(self):
        raise NotImplementedError

class bundlechangelog(bundlerevlog, changelog.changelog):
    def __init__(self, opener, cgunpacker):
        changelog.changelog.__init__(self, opener)
        linkmapper = lambda x: x
        bundlerevlog.__init__(self, opener, self.indexfile, cgunpacker,
                              linkmapper)

    def baserevision(self, nodeorrev):
        # Although changelog doesn't override 'revision' method, some extensions
        # may replace this class with another that does. Same story with
        # manifest and filelog classes.

        # This bypasses filtering on changelog.node() and rev() because we need
        # revision text of the bundle base even if it is hidden.
        oldfilter = self.filteredrevs
        try:
            self.filteredrevs = ()
            return changelog.changelog.revision(self, nodeorrev, raw=True)
        finally:
            self.filteredrevs = oldfilter

class bundlemanifest(bundlerevlog, manifest.manifestrevlog):
    def __init__(self, opener, cgunpacker, linkmapper, dirlogstarts=None,
                 dir=''):
        manifest.manifestrevlog.__init__(self, opener, dir=dir)
        bundlerevlog.__init__(self, opener, self.indexfile, cgunpacker,
                              linkmapper)
        if dirlogstarts is None:
            dirlogstarts = {}
            if self.bundle.version == "03":
                dirlogstarts = _getfilestarts(self.bundle)
        self._dirlogstarts = dirlogstarts
        self._linkmapper = linkmapper

    def baserevision(self, nodeorrev):
        node = nodeorrev
        if isinstance(node, int):
            node = self.node(node)

        if node in self.fulltextcache:
            result = '%s' % self.fulltextcache[node]
        else:
            result = manifest.manifestrevlog.revision(self, nodeorrev, raw=True)
        return result

    def dirlog(self, d):
        if d in self._dirlogstarts:
            self.bundle.seek(self._dirlogstarts[d])
            return bundlemanifest(
                self.opener, self.bundle, self._linkmapper,
                self._dirlogstarts, dir=d)
        return super(bundlemanifest, self).dirlog(d)

class bundlefilelog(bundlerevlog, filelog.filelog):
    def __init__(self, opener, path, cgunpacker, linkmapper):
        filelog.filelog.__init__(self, opener, path)
        bundlerevlog.__init__(self, opener, self.indexfile, cgunpacker,
                              linkmapper)

    def baserevision(self, nodeorrev):
        return filelog.filelog.revision(self, nodeorrev, raw=True)

class bundlepeer(localrepo.localpeer):
    def canpush(self):
        return False

class bundlephasecache(phases.phasecache):
    def __init__(self, *args, **kwargs):
        super(bundlephasecache, self).__init__(*args, **kwargs)
        if util.safehasattr(self, 'opener'):
            self.opener = vfsmod.readonlyvfs(self.opener)

    def write(self):
        raise NotImplementedError

    def _write(self, fp):
        raise NotImplementedError

    def _updateroots(self, phase, newroots, tr):
        self.phaseroots[phase] = newroots
        self.invalidate()
        self.dirty = True

def _getfilestarts(cgunpacker):
    filespos = {}
    for chunkdata in iter(cgunpacker.filelogheader, {}):
        fname = chunkdata['filename']
        filespos[fname] = cgunpacker.tell()
        for chunk in iter(lambda: cgunpacker.deltachunk(None), {}):
            pass
    return filespos

class bundlerepository(localrepo.localrepository):
    """A repository instance that is a union of a local repo and a bundle.

    Instances represent a read-only repository composed of a local repository
    with the contents of a bundle file applied. The repository instance is
    conceptually similar to the state of a repository after an
    ``hg unbundle`` operation. However, the contents of the bundle are never
    applied to the actual base repository.
    """
    def __init__(self, ui, repopath, bundlepath):
        self._tempparent = None
        try:
            localrepo.localrepository.__init__(self, ui, repopath)
        except error.RepoError:
            self._tempparent = tempfile.mkdtemp()
            localrepo.instance(ui, self._tempparent, 1)
            localrepo.localrepository.__init__(self, ui, self._tempparent)
        self.ui.setconfig('phases', 'publish', False, 'bundlerepo')

        if repopath:
            self._url = 'bundle:' + util.expandpath(repopath) + '+' + bundlepath
        else:
            self._url = 'bundle:' + bundlepath

        self.tempfile = None
        f = util.posixfile(bundlepath, "rb")
        bundle = exchange.readbundle(ui, f, bundlepath)

        if isinstance(bundle, bundle2.unbundle20):
            self._bundlefile = bundle
            self._cgunpacker = None

            cgpart = None
            for part in bundle.iterparts(seekable=True):
                if part.type == 'changegroup':
                    if cgpart:
                        raise NotImplementedError("can't process "
                                                  "multiple changegroups")
                    cgpart = part

                self._handlebundle2part(bundle, part)

            if not cgpart:
                raise error.Abort(_("No changegroups found"))

            # This is required to placate a later consumer, which expects
            # the payload offset to be at the beginning of the changegroup.
            # We need to do this after the iterparts() generator advances
            # because iterparts() will seek to end of payload after the
            # generator returns control to iterparts().
            cgpart.seek(0, os.SEEK_SET)

        elif isinstance(bundle, changegroup.cg1unpacker):
            if bundle.compressed():
                f = self._writetempbundle(bundle.read, '.hg10un',
                                          header='HG10UN')
                bundle = exchange.readbundle(ui, f, bundlepath, self.vfs)

            self._bundlefile = bundle
            self._cgunpacker = bundle
        else:
            raise error.Abort(_('bundle type %s cannot be read') %
                              type(bundle))

        # dict with the mapping 'filename' -> position in the changegroup.
        self._cgfilespos = {}

        self.firstnewrev = self.changelog.repotiprev + 1
        phases.retractboundary(self, None, phases.draft,
                               [ctx.node() for ctx in self[self.firstnewrev:]])

    def _handlebundle2part(self, bundle, part):
        if part.type != 'changegroup':
            return

        cgstream = part
        version = part.params.get('version', '01')
        legalcgvers = changegroup.supportedincomingversions(self)
        if version not in legalcgvers:
            msg = _('Unsupported changegroup version: %s')
            raise error.Abort(msg % version)
        if bundle.compressed():
            cgstream = self._writetempbundle(part.read, '.cg%sun' % version)

        self._cgunpacker = changegroup.getunbundler(version, cgstream, 'UN')

    def _writetempbundle(self, readfn, suffix, header=''):
        """Write a temporary file to disk
        """
        fdtemp, temp = self.vfs.mkstemp(prefix="hg-bundle-",
                                        suffix=suffix)
        self.tempfile = temp

        with os.fdopen(fdtemp, pycompat.sysstr('wb')) as fptemp:
            fptemp.write(header)
            while True:
                chunk = readfn(2**18)
                if not chunk:
                    break
                fptemp.write(chunk)

        return self.vfs.open(self.tempfile, mode="rb")

    @localrepo.unfilteredpropertycache
    def _phasecache(self):
        return bundlephasecache(self, self._phasedefaults)

    @localrepo.unfilteredpropertycache
    def changelog(self):
        # consume the header if it exists
        self._cgunpacker.changelogheader()
        c = bundlechangelog(self.svfs, self._cgunpacker)
        self.manstart = self._cgunpacker.tell()
        return c

    def _constructmanifest(self):
        self._cgunpacker.seek(self.manstart)
        # consume the header if it exists
        self._cgunpacker.manifestheader()
        linkmapper = self.unfiltered().changelog.rev
        m = bundlemanifest(self.svfs, self._cgunpacker, linkmapper)
        self.filestart = self._cgunpacker.tell()
        return m

    def _consumemanifest(self):
        """Consumes the manifest portion of the bundle, setting filestart so the
        file portion can be read."""
        self._cgunpacker.seek(self.manstart)
        self._cgunpacker.manifestheader()
        for delta in self._cgunpacker.deltaiter():
            pass
        self.filestart = self._cgunpacker.tell()

    @localrepo.unfilteredpropertycache
    def manstart(self):
        self.changelog
        return self.manstart

    @localrepo.unfilteredpropertycache
    def filestart(self):
        self.manifestlog

        # If filestart was not set by self.manifestlog, that means the
        # manifestlog implementation did not consume the manifests from the
        # changegroup (ex: it might be consuming trees from a separate bundle2
        # part instead). So we need to manually consume it.
        if 'filestart' not in self.__dict__:
            self._consumemanifest()

        return self.filestart

    def url(self):
        return self._url

    def file(self, f):
        if not self._cgfilespos:
            self._cgunpacker.seek(self.filestart)
            self._cgfilespos = _getfilestarts(self._cgunpacker)

        if f in self._cgfilespos:
            self._cgunpacker.seek(self._cgfilespos[f])
            linkmapper = self.unfiltered().changelog.rev
            return bundlefilelog(self.svfs, f, self._cgunpacker, linkmapper)
        else:
            return filelog.filelog(self.svfs, f)

    def close(self):
        """Close assigned bundle file immediately."""
        self._bundlefile.close()
        if self.tempfile is not None:
            self.vfs.unlink(self.tempfile)
        if self._tempparent:
            shutil.rmtree(self._tempparent, True)

    def cancopy(self):
        return False

    def peer(self):
        return bundlepeer(self)

    def getcwd(self):
        return pycompat.getcwd() # always outside the repo

    # Check if parents exist in localrepo before setting
    def setparents(self, p1, p2=nullid):
        p1rev = self.changelog.rev(p1)
        p2rev = self.changelog.rev(p2)
        msg = _("setting parent to node %s that only exists in the bundle\n")
        if self.changelog.repotiprev < p1rev:
            self.ui.warn(msg % nodemod.hex(p1))
        if self.changelog.repotiprev < p2rev:
            self.ui.warn(msg % nodemod.hex(p2))
        return super(bundlerepository, self).setparents(p1, p2)

def instance(ui, path, create):
    if create:
        raise error.Abort(_('cannot create new bundle repository'))
    # internal config: bundle.mainreporoot
    parentpath = ui.config("bundle", "mainreporoot")
    if not parentpath:
        # try to find the correct path to the working directory repo
        parentpath = cmdutil.findrepo(pycompat.getcwd())
        if parentpath is None:
            parentpath = ''
    if parentpath:
        # Try to make the full path relative so we get a nice, short URL.
        # In particular, we don't want temp dir names in test outputs.
        cwd = pycompat.getcwd()
        if parentpath == cwd:
            parentpath = ''
        else:
            cwd = pathutil.normasprefix(cwd)
            if parentpath.startswith(cwd):
                parentpath = parentpath[len(cwd):]
    u = util.url(path)
    path = u.localpath()
    if u.scheme == 'bundle':
        s = path.split("+", 1)
        if len(s) == 1:
            repopath, bundlename = parentpath, s[0]
        else:
            repopath, bundlename = s
    else:
        repopath, bundlename = parentpath, path
    return bundlerepository(ui, repopath, bundlename)

class bundletransactionmanager(object):
    def transaction(self):
        return None

    def close(self):
        raise NotImplementedError

    def release(self):
        raise NotImplementedError

def getremotechanges(ui, repo, other, onlyheads=None, bundlename=None,
                     force=False):
    '''obtains a bundle of changes incoming from other

    "onlyheads" restricts the returned changes to those reachable from the
      specified heads.
    "bundlename", if given, stores the bundle to this file path permanently;
      otherwise it's stored to a temp file and gets deleted again when you call
      the returned "cleanupfn".
    "force" indicates whether to proceed on unrelated repos.

    Returns a tuple (local, csets, cleanupfn):

    "local" is a local repo from which to obtain the actual incoming
      changesets; it is a bundlerepo for the obtained bundle when the
      original "other" is remote.
    "csets" lists the incoming changeset node ids.
    "cleanupfn" must be called without arguments when you're done processing
      the changes; it closes both the original "other" and the one returned
      here.
    '''
    tmp = discovery.findcommonincoming(repo, other, heads=onlyheads,
                                       force=force)
    common, incoming, rheads = tmp
    if not incoming:
        try:
            if bundlename:
                os.unlink(bundlename)
        except OSError:
            pass
        return repo, [], other.close

    commonset = set(common)
    rheads = [x for x in rheads if x not in commonset]

    bundle = None
    bundlerepo = None
    localrepo = other.local()
    if bundlename or not localrepo:
        # create a bundle (uncompressed if other repo is not local)

        # developer config: devel.legacy.exchange
        legexc = ui.configlist('devel', 'legacy.exchange')
        forcebundle1 = 'bundle2' not in legexc and 'bundle1' in legexc
        canbundle2 = (not forcebundle1
                      and other.capable('getbundle')
                      and other.capable('bundle2'))
        if canbundle2:
            kwargs = {}
            kwargs['common'] = common
            kwargs['heads'] = rheads
            kwargs['bundlecaps'] = exchange.caps20to10(repo)
            kwargs['cg'] = True
            b2 = other.getbundle('incoming', **kwargs)
            fname = bundle = changegroup.writechunks(ui, b2._forwardchunks(),
                                                     bundlename)
        else:
            if other.capable('getbundle'):
                cg = other.getbundle('incoming', common=common, heads=rheads)
            elif onlyheads is None and not other.capable('changegroupsubset'):
                # compat with older servers when pulling all remote heads
                cg = other.changegroup(incoming, "incoming")
                rheads = None
            else:
                cg = other.changegroupsubset(incoming, rheads, 'incoming')
            if localrepo:
                bundletype = "HG10BZ"
            else:
                bundletype = "HG10UN"
            fname = bundle = bundle2.writebundle(ui, cg, bundlename,
                                                     bundletype)
        # keep written bundle?
        if bundlename:
            bundle = None
        if not localrepo:
            # use the created uncompressed bundlerepo
            localrepo = bundlerepo = bundlerepository(repo.baseui, repo.root,
                                                      fname)
            # this repo contains local and other now, so filter out local again
            common = repo.heads()
    if localrepo:
        # Part of common may be remotely filtered
        # So use an unfiltered version
        # The discovery process probably need cleanup to avoid that
        localrepo = localrepo.unfiltered()

    csets = localrepo.changelog.findmissing(common, rheads)

    if bundlerepo:
        reponodes = [ctx.node() for ctx in bundlerepo[bundlerepo.firstnewrev:]]
        remotephases = other.listkeys('phases')

        pullop = exchange.pulloperation(bundlerepo, other, heads=reponodes)
        pullop.trmanager = bundletransactionmanager()
        exchange._pullapplyphases(pullop, remotephases)

    def cleanup():
        if bundlerepo:
            bundlerepo.close()
        if bundle:
            os.unlink(bundle)
        other.close()

    return (localrepo, csets, cleanup)