On Fri, Aug 19, 2011 at 10:10 AM, Pavel Ivanov <[email protected]> wrote:
> > If that is indeed the case, the current code will cause corruption on an > > EINTR on such platforms because the EINTR handling does not account for a > > non-0 write. > > No, it won't cause corruption. Because SQLite uses pwrite or its > alternative with calls to lseek and write. So after interruption it > will start writing at the same position it wrote previous time > rewriting part of what it has already written with the same data. > The problem comes up if SQLite is configured to not use pwrite() and instead make separate calls to lseek() followed by write(). The do-loop that retries after an EINTR was not rerunning the lseek(). I my testing a patch for for this now. http://www.sqlite.org/src/info/e59bdf6116 > > > Pavel > > > On Fri, Aug 19, 2011 at 8:48 AM, Stephan Beal <[email protected]> > wrote: > > On Thu, Aug 18, 2011 at 6:10 PM, Stephan Beal <[email protected]> > wrote: > > > >> On Thu, Aug 18, 2011 at 5:27 PM, David Garfield < > >> [email protected]> wrote: > >> > >>> I HOPE that an interrupt in a large interrupted write will NOT return > >> > >> EINTR, because if it does, the partial write is screwed up. > >>> > >> > >> i hope so, too! :-D > >> > > > > It would seem that at least one environment does allow that behaviour. > From > > the Linux write(2) man pages: > > > > ---- > > CONFORMING TO > > SVr4, 4.3BSD, POSIX.1-2001. > > > > Under SVr4 a write may be interrupted and return EINTR at any > point, > > not just before any data is written. > > ---- > > > > So this just might actually (potentially) affect some sqlite3 users. i > don't > > know if Solaris currently uses SysV or posix semantics, but Solaris was > once > > known as SVr4 (SysV, v.4)? > > > > If that is indeed the case, the current code will cause corruption on an > > EINTR on such platforms because the EINTR handling does not account for a > > non-0 write. > > > > http://kb.iu.edu/data/agjs.html > > http://en.wikipedia.org/wiki/System_V > > The German page has release dates and easier-to-read inheritance details: > > http://de.wikipedia.org/wiki/System_V > > http://en.wikipedia.org/wiki/Solaris_(operating_system) > > > > -- > > ----- stephan beal > > http://wanderinghorse.net/home/stephan/ > > _______________________________________________ > > sqlite-users mailing list > > [email protected] > > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > > _______________________________________________ > sqlite-users mailing list > [email protected] > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp [email protected] _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
