On Nov 30, 12:05 am, mabshoff <[EMAIL PROTECTED]
dortmund.de> wrote:
> Michael,
>
> there is an issue with sqlite on NFS, specifically
> fromhttp://www.sqlite.org/faq.html:
>
> SQLite uses reader/writer locks to control access to the database.
> (Under Win95/98/ME which lacks support for reader/writer locks, a
> probabilistic simulation is used instead.) But use caution: this
> locking mechanism might not work correctly if the database file is
> kept on an NFS filesystem. *This is because fcntl() file locking is
> broken on many NFS implementations. You should avoid putting SQLite
> database files on NFS if multiple processes might try to access the
> file at the same time.* On Windows, Microsoft's documentation says
> that locking may not work under FAT filesystems if you are not running
> the Share.exe daemon. People who have a lot of experience with Windows
> tell me that file locking of network files is very buggy and is not
> dependable. If what they say is true, sharing an SQLite database
> between two or more Windows machines might cause unexpected problems.
>
> So: fix you installation ;)
Actually, some more info: from http://www.sqlite.org/cvstrac/tktview?tn=1556,31
[begin quote]
2005-Dec-07 14:27:26 by drh:
This is a bug in either Gentoo linux or in your setup. SQLite is using
the fcntl(F_SETLK) interface and linux is telling SQLite that the file
is already locked. Not much SQLite can do about this.
In version 3.3.0 (or perhaps in a release soon to follow that) we will
be offering a version of SQLite that uses lockfiles rather than
fcntl() to control file access. There are disadvantages to the use of
filelocks: slower, courser grain access, and stale lockfiles that must
be manually deleted following a program crash. But lockfiles will work
on network filesystems.
2005-Dec-07 16:20:21 by anonymous:
I submitted this ticket:
It is not a bug in gentoo. Same behaviour on boxes running different
versions of SuSE (static build of my binary, executed on different
hosts within the same NFS share).
2005-Dec-08 10:56:01 by anonymous:
After realizing that it doesn't mean much if I tranfer a static build
from gentoo to SuSE, I rebuild my project from scratch on a SuSE box
(sqlite-3.2.7). Again, the results are the same: "database locked".
Since the NFS is up for about three years, it is hard to assume that
there's a config error left?! Any hints are highly appreciated!
Regards
2005-Dec-08 13:14:24 by anonymous:
Please close this ticket. The solution: I hadn't had nfs-utils
installed. After merging those and starting rpc.statd, everythings
works as expected. Sorry for the fuss.
[begin quote]
So once we update sqlite to something more current we should actually
build with lock files instead. I don't think it will have a
performance impact on our use pattern and it will make things less
likely for the user to screw up. Yi has already provided an updated
spkg, but that cause segfaults in the sfa doctest. As it turns out by
now I suspect that symmetrica is at fault in those cases, but I cannot
prove that yet. So stay tuned and use the above work around for now.
>
> Cheers,
>
> Michael
Cheers,
Michael
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