It will only pull unnecessary data when you use offset parameter in
fetch(limit,offset=0). Because when you set an offset, the datastore
still need to iterate all previous data before that offset.
On Oct 13, 1:25 pm, "David Wilson (entertainment cloud)"
<[EMAIL PROTECTED]> wrote:
> when you say the same is not true of filter, are you saying that
>
> Thing.all().filter('value >' 5).get()
>
> will pull Things 1,2,3,4,5(like the offset issue) the records from the
> datastore, but just return Things 6 from the query.
>
> this seems wrong to me.
>
> The reason im making sure on this is that my Thing has a large Blob in
> it that i really need to make sure is not getting pulled apart from
> the ones im displaying at the time. Otherwise i will split up the
> model and put an id in the Thing to a new model ThingBlob.
>
> On Oct 13, 5:34 pm, "Marzia Niccolai" <[EMAIL PROTECTED]> wrote:
>
> > Hi,
>
> > The same is not true of filter(). Filter will start at the first value
> > larger than x, and should be used if you want to paginate your records.
>
> > Brett Slatkin's IO talk covers scalable pagination recipes, and I suggest
> > checking it
> > out:http://sites.google.com/site/io/building-scalable-web-applications-wi...
>
> > -Marzia
>
> > On Mon, Oct 13, 2008 at 6:24 AM, David Wilson (entertainment cloud) <
>
> > [EMAIL PROTECTED]> wrote:
>
> > > ok, i wanted to be sure about this, as pulling all the records and
> > > just returning one would have been a performance disaster for my app.
>
> > > my question was raised because i was a little surprised to read that
> > > offset queries still pull all the 'upto' offset out of the store.
>
> > > does the same apply to Thing.all().filter('value >' x).get() ?
>
> > > and thus is it possible to page without pulling all the previous pages
> > > data from the store each time?
>
> > > On Oct 13, 1:01 pm, Sylvain <[EMAIL PROTECTED]> wrote:
> > > > Only '1'
>
> > > >http://code.google.com/appengine/docs/datastore/queryclass.html#Query...
>
> > > > On 13 oct, 13:41, "David Wilson (entertainment cloud)"
>
> > > > <[EMAIL PROTECTED]> wrote:
> > > > > Hi,
>
> > > > > class Thing(db.Model):
>
> > > > > value = db.IntegerProperty(required=True)
>
> > > > > datastore has 10 Things with value 1..10
>
> > > > > Question:
>
> > > > > How many records does the query Thing.all().order('-value').get() pull
> > > > > from the datastore?
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