On Wed, Apr 13, 2011 at 9:53 AM, Pavel Ivanov <paiva...@gmail.com> wrote:
> > The fact that one engineer installed a site, began operating the app, > > then saw it become corrupt minutes later rules out power loss or hard > > resets in at least that case. An operating system level problem should > > have been noticed by now given it's Windows XP... And the file is > > locally held too. > > I don't know how Windows's disk cache works but theoretically when you > set synchronous to OFF (0) OS can write database pages to disk in any > order it likes, disregarding the order SQLite requires. So while one > process writes those pages, another process can read those pages and > because of random writing order second process can read inconsistent > data, meaning it sees corrupted database. > Pavel, please tell me you are wrong. Surely windows maintains disk cache coherency even in the absence of explicit FlushFileBuffers() calls? Can any windows experts comment on this? > > > Pavel > > > On Wed, Apr 13, 2011 at 7:14 AM, James Green <james.mk.gr...@gmail.com> > wrote: > > Yep we've read through that. > > > > Several of the possibilities are difficult to rule out of course. They > > just seem highly unlikely (!) given the rate of corruption across our > > sites. > > > > The fact that one engineer installed a site, began operating the app, > > then saw it become corrupt minutes later rules out power loss or hard > > resets in at least that case. An operating system level problem should > > have been noticed by now given it's Windows XP... And the file is > > locally held too. > > > > Is it possible that we're seeing something nasty occurring as a result > > of anti-virus software perhaps? I might expect a higher rate of > > corruption if so. > > > > The only avenue apparently open to us is to use WAL mode. Would WAL + > > sync=normal provide a much better resistance to corruption? We > > (probably) don't care about losing the last set of SQL statements. > > > > sync=full does not work well for our app (no transactions). Far too slow. > > > > James > > > > On 13 April 2011 11:47, Richard Hipp <d...@sqlite.org> wrote: > >> On Tue, Apr 12, 2011 at 5:15 AM, James Green <james.mk.gr...@gmail.com > >wrote: > >> > >>> My question is does anyone have pointers > >>> to help us isolate the problems we are seeing. > >>> > >> > >> http://www.sqlite.org/howtocorrupt.html > >> > >> -- > >> D. Richard Hipp > >> d...@sqlite.org > >> _______________________________________________ > >> sqlite-users mailing list > >> sqlite-users@sqlite.org > >> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > >> > > _______________________________________________ > > sqlite-users mailing list > > sqlite-users@sqlite.org > > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
