[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

Re: "FSFS": Subversion filesystem implementation?

From: J Robert Ray <jrray_at_imageworks.com>
Date: 2004-10-13 04:36:40 CEST

Eric Gillespie wrote:
> J Robert Ray <jrray@imageworks.com> writes:
>
>
>>I am interested in moving to fsfs, but the way it fills a
>>directory with a file per revision makes me nervous.
>
>
> Don't worry about it. Subversion never scans these directories.
> The only cost is going to be in using non-svn tools, which is not
> necessary. svnadmin hotcopy/dump should satisfy backup needs.
> Or you could just do what i'm doing and copy the revprops, revs,
> and current files in post-commit. But there's never a need to
> scan these directories.
>
>
>>I'm afraid there may be a breaking point of performance with a
>>large number of revs. A quick strace of a svn blame shows
>>1,860 calls to open() on files in db/revs.
>
>
> open's speed is not affected by the number of entries in a
> directory.

This isn't exactly true, but there is some directory entry caching that
helps:

http://groups.google.com/groups?hl=en&lr=&c2coff=1&client=firefox&selm=9ff6aq%242l3%241%40cesium.transmeta.com

I would qualify your statement by saying there are unavoidable startup
costs and RAM requirements to keep performance at acceptable levels.

- Robert

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@subversion.tigris.org
For additional commands, e-mail: users-help@subversion.tigris.org
Received on Wed Oct 13 04:38:13 2004

This is an archived mail posted to the Subversion Users mailing list.

This site is subject to the Apache Privacy Policy and the Apache Public Forum Archive Policy.