martinvonz created this revision. Herald added a subscriber: mercurial-devel. Herald added a reviewer: hg-reviewers.
REVISION SUMMARY As explained in the bug report, this commit caused a performance regression. The problem occurs when the local repo has very many heads. Before https://phab.mercurial-scm.org/rHG5cfdf6137af87e52063a5a11a697bab805e4b03d, we used to get the remote's list of heads and if these heads mostly overlapped with the local repo's heads, we would mark these common heads as common, which would greatly reduce the size of the set of undecided nodes. Note that a similar problem existed before https://phab.mercurial-scm.org/rHG5cfdf6137af87e52063a5a11a697bab805e4b03d: If the local repo had very many heads and the server just had a few (or many heads from a disjoint set), we would do the same kind of slow discovery as we would with https://phab.mercurial-scm.org/rHG5cfdf6137af87e52063a5a11a697bab805e4b03d in the case where local and remote repos share a large set of common nodes. For now, we just back out https://phab.mercurial-scm.org/rHG5cfdf6137af87e52063a5a11a697bab805e4b03d. We should improve the discovery in the "local has many heads, remote has few heads" case, but let's do that after backing this out. REPOSITORY rHG Mercurial REVISION DETAIL https://phab.mercurial-scm.org/D2643 AFFECTED FILES mercurial/discovery.py mercurial/setdiscovery.py CHANGE DETAILS diff --git a/mercurial/setdiscovery.py b/mercurial/setdiscovery.py --- a/mercurial/setdiscovery.py +++ b/mercurial/setdiscovery.py @@ -130,7 +130,7 @@ sample = set(random.sample(sample, desiredlen)) return sample -def findcommonheads(ui, local, remote, heads=None, +def findcommonheads(ui, local, remote, initialsamplesize=100, fullsamplesize=200, abortwhenunrelated=True, @@ -155,15 +155,11 @@ sample = _limitsample(ownheads, initialsamplesize) # indices between sample and externalized version must match sample = list(sample) - if heads: - srvheadhashes = heads - yesno = remote.known(dag.externalizeall(sample)) - else: - batch = remote.iterbatch() - batch.heads() - batch.known(dag.externalizeall(sample)) - batch.submit() - srvheadhashes, yesno = batch.results() + batch = remote.iterbatch() + batch.heads() + batch.known(dag.externalizeall(sample)) + batch.submit() + srvheadhashes, yesno = batch.results() if cl.tip() == nullid: if srvheadhashes != [nullid]: diff --git a/mercurial/discovery.py b/mercurial/discovery.py --- a/mercurial/discovery.py +++ b/mercurial/discovery.py @@ -57,7 +57,7 @@ if all(knownnode(h) for h in heads): return (heads, False, heads) - res = setdiscovery.findcommonheads(repo.ui, repo, remote, heads, + res = setdiscovery.findcommonheads(repo.ui, repo, remote, abortwhenunrelated=not force, ancestorsof=ancestorsof) common, anyinc, srvheads = res To: martinvonz, #hg-reviewers Cc: mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
