Mercurial > hg
view mercurial/setdiscovery.py @ 17013:c8eda7bbdcab
strip: incrementally update the branchheads cache after a strip
This function augments strip to incrementally update the branchheads cache
rather than recompute it from scratch. This speeds up the performance of strip
and rebase on repos with long history. The performance optimization only
happens if the revisions stripped are all on the same branch and the parents of
the stripped revisions are also on that same branch.
This adds a few test cases, particularly one that reproduces the extra heads
that mpm observed.
author | Joshua Redstone <joshua.redstone@fb.com> |
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date | Fri, 18 May 2012 12:45:47 -0700 |
parents | cafd8a8fb713 |
children | 5884812686f7 |
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# setdiscovery.py - improved discovery of common nodeset for mercurial # # Copyright 2010 Benoit Boissinot <bboissin@gmail.com> # and Peter Arrenbrecht <peter@arrenbrecht.ch> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from node import nullid from i18n import _ import random, util, dagutil import phases def _updatesample(dag, nodes, sample, always, quicksamplesize=0): # if nodes is empty we scan the entire graph if nodes: heads = dag.headsetofconnecteds(nodes) else: heads = dag.heads() dist = {} visit = util.deque(heads) seen = set() factor = 1 while visit: curr = visit.popleft() if curr in seen: continue d = dist.setdefault(curr, 1) if d > factor: factor *= 2 if d == factor: if curr not in always: # need this check for the early exit below sample.add(curr) if quicksamplesize and (len(sample) >= quicksamplesize): return seen.add(curr) for p in dag.parents(curr): if not nodes or p in nodes: dist.setdefault(p, d + 1) visit.append(p) def _setupsample(dag, nodes, size): if len(nodes) <= size: return set(nodes), None, 0 always = dag.headsetofconnecteds(nodes) desiredlen = size - len(always) if desiredlen <= 0: # This could be bad if there are very many heads, all unknown to the # server. We're counting on long request support here. return always, None, desiredlen return always, set(), desiredlen def _takequicksample(dag, nodes, size, initial): always, sample, desiredlen = _setupsample(dag, nodes, size) if sample is None: return always if initial: fromset = None else: fromset = nodes _updatesample(dag, fromset, sample, always, quicksamplesize=desiredlen) sample.update(always) return sample def _takefullsample(dag, nodes, size): always, sample, desiredlen = _setupsample(dag, nodes, size) if sample is None: return always # update from heads _updatesample(dag, nodes, sample, always) # update from roots _updatesample(dag.inverse(), nodes, sample, always) assert sample if len(sample) > desiredlen: sample = set(random.sample(sample, desiredlen)) elif len(sample) < desiredlen: more = desiredlen - len(sample) sample.update(random.sample(list(nodes - sample - always), more)) sample.update(always) return sample def findcommonheads(ui, local, remote, initialsamplesize=100, fullsamplesize=200, abortwhenunrelated=True): '''Return a tuple (common, anyincoming, remoteheads) used to identify missing nodes from or in remote. shortcutlocal determines whether we try use direct access to localrepo if remote is actually local. ''' roundtrips = 0 cl = local.changelog dag = dagutil.revlogdag(cl) # early exit if we know all the specified remote heads already ui.debug("query 1; heads\n") roundtrips += 1 ownheads = dag.heads() sample = ownheads if remote.local(): # stopgap until we have a proper localpeer that supports batch() srvheadhashes = phases.visibleheads(remote) yesno = remote.known(dag.externalizeall(sample)) elif remote.capable('batch'): batch = remote.batch() srvheadhashesref = batch.heads() yesnoref = batch.known(dag.externalizeall(sample)) batch.submit() srvheadhashes = srvheadhashesref.value yesno = yesnoref.value else: # compatibitity with pre-batch, but post-known remotes during 1.9 devel srvheadhashes = remote.heads() sample = [] if cl.tip() == nullid: if srvheadhashes != [nullid]: return [nullid], True, srvheadhashes return [nullid], False, [] # start actual discovery (we note this before the next "if" for # compatibility reasons) ui.status(_("searching for changes\n")) srvheads = dag.internalizeall(srvheadhashes, filterunknown=True) if len(srvheads) == len(srvheadhashes): ui.debug("all remote heads known locally\n") return (srvheadhashes, False, srvheadhashes,) if sample and util.all(yesno): ui.note(_("all local heads known remotely\n")) ownheadhashes = dag.externalizeall(ownheads) return (ownheadhashes, True, srvheadhashes,) # full blown discovery # own nodes where I don't know if remote knows them undecided = dag.nodeset() # own nodes I know we both know common = set() # own nodes I know remote lacks missing = set() # treat remote heads (and maybe own heads) as a first implicit sample # response common.update(dag.ancestorset(srvheads)) undecided.difference_update(common) full = False while undecided: if sample: commoninsample = set(n for i, n in enumerate(sample) if yesno[i]) common.update(dag.ancestorset(commoninsample, common)) missinginsample = [n for i, n in enumerate(sample) if not yesno[i]] missing.update(dag.descendantset(missinginsample, missing)) undecided.difference_update(missing) undecided.difference_update(common) if not undecided: break if full: ui.note(_("sampling from both directions\n")) sample = _takefullsample(dag, undecided, size=fullsamplesize) elif common: # use cheapish initial sample ui.debug("taking initial sample\n") sample = _takefullsample(dag, undecided, size=fullsamplesize) else: # use even cheaper initial sample ui.debug("taking quick initial sample\n") sample = _takequicksample(dag, undecided, size=initialsamplesize, initial=True) roundtrips += 1 ui.progress(_('searching'), roundtrips, unit=_('queries')) ui.debug("query %i; still undecided: %i, sample size is: %i\n" % (roundtrips, len(undecided), len(sample))) # indices between sample and externalized version must match sample = list(sample) yesno = remote.known(dag.externalizeall(sample)) full = True result = dag.headsetofconnecteds(common) ui.progress(_('searching'), None) ui.debug("%d total queries\n" % roundtrips) if not result and srvheadhashes != [nullid]: if abortwhenunrelated: raise util.Abort(_("repository is unrelated")) else: ui.warn(_("warning: repository is unrelated\n")) return (set([nullid]), True, srvheadhashes,) anyincoming = (srvheadhashes != [nullid]) return dag.externalizeall(result), anyincoming, srvheadhashes