Some unscientific timing results (on the Python source tree)
John Arbash Meinel
john at arbash-meinel.com
Mon Mar 31 16:21:41 BST 2008
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Jelmer Vernooij wrote:
| On Mo, 2008-03-31 at 11:17 +1000, Ian Clatworthy wrote:
|> Paul Moore wrote:
|>> On 27/03/2008, John Arbash Meinel <john at arbash-meinel.com> wrote:
|>>> Paul Moore wrote:
|>>> |
|>>> | bzr - 262Mb
|>>> | hg - 140Mb
|>>> | Subversion checkout - 333Mb
|>>>
|>>> Something seems fishy here. Specifically, if the SVN checkout is 333Mb, that
|>> I'm using rich-root-pack, because the source came from bzr-svn, but
|>> otherwise no issues.
|> As I've just mentioned in another thread, repositories converted via
|> bzr-svn use a different scheme for revision ids to what Bazaar does by
|> default, leading to a different sized repo than that converted by other
|> means. I'm yet to measure the difference myself so I'd be interested in
|> seeing some numbers if anyone has them.
| The difference in length isn't really significant:
|
| A bzr-svn-generated revision id:
|
| svn-v3-trunk0:e8204dac-47fa-0310-9482-a4e8a03ab89e:trunk:67
|
| A "regular" revision id:
|
| jelmer at samba.org-20071225174917-vkh3hrm75fd523v7
|
| So I don't see how that could lead to significantly larger repositories.
|
| Cheers,
|
| Jelmer
|
30k revisions * 11 characters = 330k bytes. It is probably repeated a couple of
times, so you are talking ~1MB worth of data from the revision id in index
files. And then in inventories you have 2 file ids + 1 revision id, so it is an
extra what... 30 bytes per line, 4000 lines per inventory, 30k inventories (lots
of them deltas.)
I would probably worry more about the size of the file-ids, as I believe those
get excessively long.
I won't say it is a huge difference, maybe 1% for indexes, not sure how much it
effects inventories. Certainly not nearly as much as allowing the number of
deltas to grow beyond 200 for large trees. (I'm not sure how much it would
effect smaller trees, as we have a "fulltext whenever size(deltas) >
size(fulltext)".
John
=:->
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