>>The integrity check just takes too long so we don't.
pragma quick_check; doesn't take much tme.
http://www.sqlite.org/pragma.html#pragma_quick_check
On Sun, Mar 3, 2013 at 8:00 AM, Jason Dictos <jdic...@barracuda.com> wrote:
> >> .
> >
> > Thanks for the details. What programming language do you use? (Dropbox
> > uses Python.)
> >
>
> C++
>
> >> Early on we figured out quite quickly not leverage the read/write
> >> locking models of SQLite
> >
> > Do you use WAL mode?
> >
>
> I played with it early on but I didn't know how stable the feature was and
> didn't need any of its features at the time, so not at this time.
>
> > I'm also curious roughly what you do with your schema. It looks like the
> > Dropbox on Android schema has elements of implementing a tree with
> > everything in one big table and no triggers.
> >
>
> We have a file table which is our representation of what the cloud
> currently thinks of things. Then we diff what the filesystem thinks and
> describe the differences to the cloud. Once the cloud accepts the event we
> update our file table. We are careful with triggers and foreign keys since
> SQLite slows to a crawl when we have those and decide to delete a few
> thousand rows.
>
> > Do you use any of SQLite's extensibilty such as adding your own
> collations
> > or user defined functions.
> >
>
> We did have some stored procedures early on but we soon found ways to use
> the sql language a bit better, which is always a faster option and
> guarantees use of indices in some cases. We still may have a couple I think
> but they are not used very much.
>
> >> As it stands now, our customers periodically have random I/O errors
> >> ...
> >
> > As you have large deployments, random stuff does happen. We have a web
> > service with several requests per second from browsers all over the world
> > and sadly have to use HTTP (cough *IE* cough) rather than the SSL we
> > normally use. Even though TCP/IP is checksummed there are sporadic
> > corruptions that come through (typically bit flips here and there).
> >
> > 8 years ago there were lots of CPU random errors:
> >
> > http://blogs.msdn.com/b/oldnewthing/archive/2005/04/12/407562.aspx
> >
> > Do you run an integrity check at startup on the database? I did so with
> > BitPim, but we didn't have analytics so there was no idea how often
> > corruption happened.
> >
>
> The integrity check just takes too long so we don't. We are currently
> brainstorming ways of detecting corruption quickly.
>
> > There has been an open feature request for a while to have data checksums
> > to deal with the case that what SQLite thinks it wrote is not what is
> > later returned:
> >
> > http://www.sqlite.org/src/tktview?name=72b01a982a
> >
>
> Thanks for the info Roger
>
> Jason
>
> > -----BEGIN PGP SIGNATURE-----
> > Version: GnuPG v1.4.11 (GNU/Linux)
> >
> > iEYEARECAAYFAlExZhYACgkQmOOfHg372QTLBgCgsbidy6oQfmAeS4OWq4OBSmFI
> > zxEAn04lneghgvr+ww76AQWzycZ3x+Q0
> > =eya6
> > -----END PGP SIGNATURE-----
> > _______________________________________________
> > sqlite-users mailing list
> > sqlite-users@sqlite.org
> > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
> Copy, by Barracuda, helps you store, protect, and share all your amazing
> things. Start today: www.copy.com.
> _______________________________________________
> 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
