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Re: Idea for reducing disk IO on tagging operations
From: |
Dr. David Alan Gilbert |
Subject: |
Re: Idea for reducing disk IO on tagging operations |
Date: |
Wed, 23 Mar 2005 01:21:53 +0000 |
User-agent: |
Mutt/1.5.6+20040907i |
* Mark D. Baushke (address@hidden) wrote:
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> Paul Sander <address@hidden> writes:
>
> Actually, if you look closely, I believe that CVS will not do read-only
> RCS operations if a CVS write-lock exists for the directory. Of course,
> ViewCVS and CVSweb do it all the time as do many of the other add-ons.
I'm getting more worried about this one for 2 seperate reasons:
1) There is talk of cvs -n for diff and the like which seems to
suggest it ignores locks.
2) I could do with a better under standing of the directory locks;
pointers? I've read the top of lock.c but it still doesn't tell me
enough; for example there seem to be multiple lock files used - but
then surely the creation of them isn't atomic? Or is there one lock
file used for both reading and writing?
> > There's also the interrupt issue: Killing an update before it
> > completes leaves the RCS file corrupt. You'd have to build in some
> > kind of crash recovery. But RCS already has that by way of the comma
> > file, which can simply be deleted. Other crash recovery algorithms
> > usually involve transaction logs that can be reversed and replayed, or
> > the creation of backup copies. None of these are more efficient than
> > the existing RCS update protocol.
>
> Agreed. This is a very big deal.
Actually I'm becoming less worried by this; I'm failing to see any way
that a single system call write() to a block not crossing a block
boundary could partially fail; but I'm up for suggestions.
Dave
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux on Alpha,68K| Happy \
\ gro.gilbert @ treblig.org | MIPS,x86,ARM,SPARC,PPC & HPPA | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
- Re: Idea for reducing disk IO on tagging operations, (continued)
- Re: Idea for reducing disk IO on tagging operations, Dr. David Alan Gilbert, 2005/03/20
- Re: Idea for reducing disk IO on tagging operations, Mark D. Baushke, 2005/03/20
- Re: Idea for reducing disk IO on tagging operations, Dr. David Alan Gilbert, 2005/03/20
- Re: Idea for reducing disk IO on tagging operations, Paul Sander, 2005/03/20
- Re: Idea for reducing disk IO on tagging operations, Mark D. Baushke, 2005/03/21
- Re: Idea for reducing disk IO on tagging operations, Todd Denniston, 2005/03/21
- Re: Idea for reducing disk IO on tagging operations, Mark D. Baushke, 2005/03/21
- Re: Idea for reducing disk IO on tagging operations, Spiro Trikaliotis, 2005/03/30
Re: Idea for reducing disk IO on tagging operations, Tony Aiuto, 2005/03/21
Re: Idea for reducing disk IO on tagging operations,
Dr. David Alan Gilbert <=
Re: Idea for reducing disk IO on tagging operations, Paul Sander, 2005/03/22
RE: Idea for reducing disk IO on tagging operations, Jim.Hyslop, 2005/03/28