From: Tomas Mraz <t8m@centrum•cz>
To: Denys Duchier <duchier@ps•uni-sb.de>
Cc: gnu-arch-dev@lists•seyza.com, talli@museatech•net, git@vger•kernel.org
Subject: Re: [Gnu-arch-users] Re: [GNU-arch-dev] [ANNOUNCEMENT] /Arch/ embraces `git'
Date: Thu, 21 Apr 2005 12:21:16 +0200 [thread overview]
Message-ID: <1114078877.5886.37.camel@perun.redhat.usu> (raw)
In-Reply-To: <86d5soa42h.fsf@speedy.lifl.fr>
On Thu, 2005-04-21 at 11:09 +0200, Denys Duchier wrote:
> Tomas Mraz <t8m@centrum•cz> writes:
>
> > If we suppose the maximum number of stored blobs in the order of milions
> > probably the optimal indexing would be 1 level [0:2] indexing or 2
> > levels [0:1] [2:3]. However it would be necessary to do some
> > benchmarking first before setting this to stone.
>
> As I have suggested in a previous message, it is trivial to implement adaptive
> indexing: there is no need to hardwire a specific indexing scheme. Furthermore,
> I suspect that the optimal size of subkeys may well depend on the filesystem.
> My experiments seem to indicate that subkeys of length 2 achieve an excellent
> compromise between discriminatory power and disk footprint on ext2.
>
> Btw, if, as you indicate above, you do believe that a 1 level indexing should
> use [0:2], then it doesn't make much sense to me to also suggest that a 2 level
> indexing should use [0:1] as primary subkey :-)
Why do you think so? IMHO we should always target a similar number of
files/subdirectories in a directories of the blob archive. So If I
always suppose that the archive would contain at most 16 millions of
files then the possible indexing schemes are either 1 level with key
length 3 (each directory would contain ~4096 files) or 2 level with key
length 2 (each directory would contain ~256 files).
Which one is better could be of course filesystem and hardware
dependent.
Of course it might be best to allow adaptive indexing but I think that
first some benchmarking should be made and it's possible that some fixed
scheme could be chosen as optimal.
--
Tomas Mraz <t8m@centrum•cz>
next prev parent reply other threads:[~2005-04-21 10:17 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-20 10:00 [ANNOUNCEMENT] /Arch/ embraces `git' Tom Lord
2005-04-20 10:19 ` Miles Bader
2005-04-20 17:15 ` duchier
2005-04-20 22:40 ` [Gnu-arch-users] Re: [GNU-arch-dev] " Tomas Mraz
2005-04-21 9:09 ` Denys Duchier
2005-04-21 10:21 ` Tomas Mraz [this message]
2005-04-21 11:46 ` [Gnu-arch-users] " duchier
2005-04-20 22:51 ` Tomas Mraz
2005-04-21 19:04 ` Tom Lord
2005-04-21 20:35 ` [Gnu-arch-users] Re: [GNU-arch-dev] " Tom Lord
2005-04-20 23:04 ` Tom Lord
2005-04-21 0:05 ` [Gnu-arch-users] Re: [GNU-arch-dev] " Denys Duchier
2005-04-21 20:39 ` [Gnu-arch-users] " Tom Lord
2005-04-21 7:49 ` Tomas Mraz
2005-04-21 21:51 ` [Gnu-arch-users] Re: [GNU-arch-dev] " Tom Lord
2005-04-21 21:52 ` Tom Lord
2005-04-22 16:13 ` Linus Torvalds
2005-04-22 17:39 ` Edésio Costa e Silva
2005-04-20 21:31 ` Petr Baudis
2005-04-20 21:55 ` C. Scott Ananian
2005-04-20 22:22 ` chunking (Re: [ANNOUNCEMENT] /Arch/ embraces `git') Linus Torvalds
2005-04-20 23:42 ` C. Scott Ananian
2005-04-22 21:02 ` blowing chunks (quick update) C. Scott Ananian
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