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On Monday 27 March 2006 10:29, Paul de Vrieze wrote: |
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> On Monday 27 March 2006 07:43, Ryan Phillips wrote: |
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> > In actuality, Subversion does 98% of the commit in an initial |
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> > transaction, and the blocking only occurs in the last 2% with the FSFS |
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> > filesystem. It really isn't an issue and shouldn't prevent us from |
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> > adopting it. |
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> |
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> Indeed, subversion first uploads the stuff, only then creates a new |
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> revision. In any case one does not want multiple commits at the same time |
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> in any case. For full portage the problems are more likely to be with svn |
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> update. One can expect there will be a lot more updates than commits. As |
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> the commits done are fairly small, those should not be an issue. Updates |
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> work on the whole tree however. Initial checkouts are worse, because they |
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> require the head to be reassembled (IIRC). Head checkout could be cached |
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> though (but I don't think that's done currently). |
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|
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This thread [1] from subversion-users asked about update/checkout performance. |
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The svn people answered that performance usually isn't constrained by |
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reassembly time. Moreover, the older BDB repo format stores the complete |
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latest revision, and checkouts aren't significantly faster than from FSFS. |
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|
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(Of course, if SVN working copies didn't contain two complete copies of the |
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stored data plus some fat metadata, then reassembly time would likely affect |
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checkout time.) |
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|
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[2] explains the SVN skip-deltas storage method. |
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Disclaimer, I haven't run any huge-repo benchmarks myself, just pointing to |
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possibly relevant data. |
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[1] http://svn.haxx.se/users/archive-2005-04/0518.shtml |
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[2] http://svn.collab.net/repos/svn/trunk/notes/skip-deltas |
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-- |
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Dan Armak |
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Gentoo Linux developer (KDE) |
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Public GPG key: http://dev.gentoo.org/~danarmak/danarmak-gpg-public.key |
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Fingerprint: DD70 DBF9 E3D4 6CB9 2FDD 0069 508D 9143 8D5F 8951 |