Mercurial > hg
view mercurial/repair.py @ 24735:07200e3332a1
tags: extract .hgtags filenodes cache to a standalone file
Resolution of .hgtags filenodes values has historically been a
performance pain point for large repositories, where reading individual
manifests can take over 100ms. Multiplied by hundreds or even thousands
of heads and resolving .hgtags filenodes becomes a performance issue.
This patch establishes a standalone cache file holding the .hgtags
filenodes for each changeset. After this patch, the .hgtags filenode
for any particular changeset should only have to be computed once
during the lifetime of the repository.
The introduced hgtagsfnodes1 cache file is modeled after the rev branch
cache: the cache is effectively an array of entries consisting of a
changeset fragment and the filenode for a revision. The file grows in
proportion to the length of the repository (24 bytes per changeset) and
is truncated when the repository is stripped. The file is not written
unless tag info is requested and tags have changed since last time.
This patch partially addresses issue4550. Future patches will split the
"tags" cache file into per-filter files and will refactor the cache
format to not capture the .hgtags fnodes, as these are now stored in
the hgtagsfnodes1 cache. This patch is capable of standing alone. We
should not have to wait on the tags cache filter split and format
refactor for this patch to land.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 15 Apr 2015 17:42:38 -0400 |
parents | e0e28e910fa3 |
children | f3558829471b |
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# repair.py - functions for repository repair for mercurial # # Copyright 2005, 2006 Chris Mason <mason@suse.com> # Copyright 2007 Matt Mackall # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from mercurial import changegroup, exchange, util, bundle2 from mercurial.node import short, hex from mercurial.i18n import _ import errno def _bundle(repo, bases, heads, node, suffix, compress=True): """create a bundle with the specified revisions as a backup""" usebundle2 = (repo.ui.config('experimental', 'bundle2-exp') and repo.ui.config('experimental', 'strip-bundle2-version')) if usebundle2: cgversion = repo.ui.config('experimental', 'strip-bundle2-version') if cgversion not in changegroup.packermap: repo.ui.warn(_('unknown strip-bundle2-version value %r; ' + 'should be one of %r\n') % (cgversion, sorted(changegroup.packermap.keys()),)) cgversion = '01' usebundle2 = False else: cgversion = '01' cg = changegroup.changegroupsubset(repo, bases, heads, 'strip', version=cgversion) backupdir = "strip-backup" vfs = repo.vfs if not vfs.isdir(backupdir): vfs.mkdir(backupdir) # Include a hash of all the nodes in the filename for uniqueness hexbases = (hex(n) for n in bases) hexheads = (hex(n) for n in heads) allcommits = repo.set('%ls::%ls', hexbases, hexheads) allhashes = sorted(c.hex() for c in allcommits) totalhash = util.sha1(''.join(allhashes)).hexdigest() name = "%s/%s-%s-%s.hg" % (backupdir, short(node), totalhash[:8], suffix) if usebundle2: bundletype = "HG20" elif compress: bundletype = "HG10BZ" else: bundletype = "HG10UN" return changegroup.writebundle(repo.ui, cg, name, bundletype, vfs) def _collectfiles(repo, striprev): """find out the filelogs affected by the strip""" files = set() for x in xrange(striprev, len(repo)): files.update(repo[x].files()) return sorted(files) def _collectbrokencsets(repo, files, striprev): """return the changesets which will be broken by the truncation""" s = set() def collectone(revlog): _, brokenset = revlog.getstrippoint(striprev) s.update([revlog.linkrev(r) for r in brokenset]) collectone(repo.manifest) for fname in files: collectone(repo.file(fname)) return s def strip(ui, repo, nodelist, backup=True, topic='backup'): # Simple way to maintain backwards compatibility for this # argument. if backup in ['none', 'strip']: backup = False repo = repo.unfiltered() repo.destroying() cl = repo.changelog # TODO handle undo of merge sets if isinstance(nodelist, str): nodelist = [nodelist] striplist = [cl.rev(node) for node in nodelist] striprev = min(striplist) # Some revisions with rev > striprev may not be descendants of striprev. # We have to find these revisions and put them in a bundle, so that # we can restore them after the truncations. # To create the bundle we use repo.changegroupsubset which requires # the list of heads and bases of the set of interesting revisions. # (head = revision in the set that has no descendant in the set; # base = revision in the set that has no ancestor in the set) tostrip = set(striplist) for rev in striplist: for desc in cl.descendants([rev]): tostrip.add(desc) files = _collectfiles(repo, striprev) saverevs = _collectbrokencsets(repo, files, striprev) # compute heads saveheads = set(saverevs) for r in xrange(striprev + 1, len(cl)): if r not in tostrip: saverevs.add(r) saveheads.difference_update(cl.parentrevs(r)) saveheads.add(r) saveheads = [cl.node(r) for r in saveheads] # compute base nodes if saverevs: descendants = set(cl.descendants(saverevs)) saverevs.difference_update(descendants) savebases = [cl.node(r) for r in saverevs] stripbases = [cl.node(r) for r in tostrip] # For a set s, max(parents(s) - s) is the same as max(heads(::s - s)), but # is much faster newbmtarget = repo.revs('max(parents(%ld) - (%ld))', tostrip, tostrip) if newbmtarget: newbmtarget = repo[newbmtarget.first()].node() else: newbmtarget = '.' bm = repo._bookmarks updatebm = [] for m in bm: rev = repo[bm[m]].rev() if rev in tostrip: updatebm.append(m) # create a changegroup for all the branches we need to keep backupfile = None vfs = repo.vfs node = nodelist[-1] if backup: backupfile = _bundle(repo, stripbases, cl.heads(), node, topic) repo.ui.status(_("saved backup bundle to %s\n") % vfs.join(backupfile)) repo.ui.log("backupbundle", "saved backup bundle to %s\n", vfs.join(backupfile)) if saveheads or savebases: # do not compress partial bundle if we remove it from disk later chgrpfile = _bundle(repo, savebases, saveheads, node, 'temp', compress=False) mfst = repo.manifest tr = repo.transaction("strip") offset = len(tr.entries) try: tr.startgroup() cl.strip(striprev, tr) mfst.strip(striprev, tr) for fn in files: repo.file(fn).strip(striprev, tr) tr.endgroup() try: for i in xrange(offset, len(tr.entries)): file, troffset, ignore = tr.entries[i] repo.svfs(file, 'a').truncate(troffset) if troffset == 0: repo.store.markremoved(file) tr.close() except: # re-raises tr.abort() raise if saveheads or savebases: ui.note(_("adding branch\n")) f = vfs.open(chgrpfile, "rb") gen = exchange.readbundle(ui, f, chgrpfile, vfs) if not repo.ui.verbose: # silence internal shuffling chatter repo.ui.pushbuffer() if isinstance(gen, bundle2.unbundle20): tr = repo.transaction('strip') tr.hookargs = {'source': 'strip', 'url': 'bundle:' + vfs.join(chgrpfile)} try: bundle2.processbundle(repo, gen, lambda: tr) tr.close() finally: tr.release() else: changegroup.addchangegroup(repo, gen, 'strip', 'bundle:' + vfs.join(chgrpfile), True) if not repo.ui.verbose: repo.ui.popbuffer() f.close() # remove undo files for undovfs, undofile in repo.undofiles(): try: undovfs.unlink(undofile) except OSError, e: if e.errno != errno.ENOENT: ui.warn(_('error removing %s: %s\n') % (undovfs.join(undofile), str(e))) for m in updatebm: bm[m] = repo[newbmtarget].node() bm.write() except: # re-raises if backupfile: ui.warn(_("strip failed, full bundle stored in '%s'\n") % vfs.join(backupfile)) elif saveheads: ui.warn(_("strip failed, partial bundle stored in '%s'\n") % vfs.join(chgrpfile)) raise else: if saveheads or savebases: # Remove partial backup only if there were no exceptions vfs.unlink(chgrpfile) repo.destroyed()