If you have a composite index, the performance of this query should be
mostly linear (find start location of index and just return min(2000, number
of entities that satisfy query from there on out) number of keys and items.
If you only have individual indexes for SheetMetadataId as well as
InstanceAssignedTo, this uses zigzag merge join, where performance can
greatly vary depending on the shape of the data.
Just out of curiosity, what is the performance of this query?
q = db.Query(PrimaryData)
q.filter('SheetMetadataId', metadata.getSheetId())
return q.fetch(2000)
If it's in a similar ballpark, my other guess is that the query takes that
amount of time because the entities are large.
You mentioned created a composite index. Can you post that?
I'll talk to the datastore team to see what we can do to provide something
similar to EXPLAIN plans for queries.
Ikai Lan
Developer Programs Engineer, Google App Engine
Blog: http://googleappengine.blogspot.com
Twitter: http://twitter.com/app_engine
Reddit: http://www.reddit.com/r/appengine
On Thu, Mar 17, 2011 at 10:07 AM, adhi <adhinaraya...@gmail.com> wrote:
> Hi Robert,
> I've not used reference properties. Its a simple query and it'll be
> like this.
>
> q = db.Query(PrimaryData)
> q.filter('SheetMetadataId', metadata.getSheetId())
> q.filter('InstanceAssignedTo IN',
> [u'User_c42e8919_448e_11e0_b87b_f58d20c6e2c3',
> u'User_1fd87ac5_073d_11e0_8ba1_c122a5867c4a'])
> return q.fetch(2000)
>
> and I replaced the IN filter to '=' with single value. Still its
> taking same time.
>
>
>
> On Mar 17, 6:27 am, Robert Kluin <robert.kl...@gmail.com> wrote:
> > Use Appstats. It may not be the query that is slow. If you are using
> > reference properties, perhaps you are dereferencing them. If you
> > should us the query and how you're using the results we might be abel
> > to give more suggestions.
> >
> > http://code.google.com/appengine/docs/python/tools/appstats.html
> >
> > Robert
> >
> >
> >
> >
> >
> >
> >
> > On Mon, Mar 14, 2011 at 10:54, adhi <adhinaraya...@gmail.com> wrote:
> > > Hi, I'm running a query in appengine which is returning just 1200
> > > entities, but its taking 3.5 seconds. The query doesn't contains
> > > inequality filters, but anyway I added index for that. Can anyone tell
> > > me how to analyse this and improve theperformance?
> >
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