thank you Nick. I will then also use ArrayProperty in my Models ! I really thought that I could use ListProperty with indexed=False, just as a quick and cheap list.
On Sep 1, 1:56 pm, "Nick Johnson (Google)" <[email protected]> wrote: > Hi Philippe, > > On Tue, Sep 1, 2009 at 12:43 PM, Philippe <[email protected]> wrote: > > > hello Nick, > > > Why do you advice using ArrayProperty instead of db.ListProperty > > (float, indexed=False) > > with the indexed=False, it should behave the same way, no ? > > A ListProperty requires encoding each element of the list as a separate > property entry in the Entity Protocol Buffer. Protocol Buffer encoding in > Python is less efficient than simple array encoding (which is extremely > straightforward), and you also incur the additional overhead of serializing > the key multiple times - eg, a 1000 entry list is serialized as 1000 (key, > value) pairs. > > -Nick Johnson > > > > > > > Philippe > > > On Sep 1, 11:48 am, "Nick Johnson (Google)" <[email protected]> > > wrote: > > > Hi John, > > > You might also want to look at the ArrayProperty in the App Engine > > > Cookbook: > >http://appengine-cookbook.appspot.com/recipe/store-arrays-of-numeric-.... > > > Pickling is not particularly efficient, so using an Array is likely to > > > be > > > both faster and more compact. > > > > -Nick Johnson > > > > On Tue, Sep 1, 2009 at 4:55 AM, John Newlin <[email protected]> wrote: > > > > > Did some more trial and error, and found that if I change the > > > > ListProperty(float) to BlobProperty with pickled data, the time for > > > > queries goes down from 700ms to 70ms, which seems pretty reasonable. > > > > > -john > > > > > On Sun, Aug 30, 2009 at 2:08 PM, jnewlin<[email protected]> wrote: > > > > > Hi all, > > > > > > I'm seeing from the logs that my query is taking 400ms up to around > > > > > 1000ms. My model looks like: > > > > > class Track2(db.Model): > > > > > name = db.StringProperty(required=True) > > > > > date = db.StringProperty(required=True) > > > > > max_speed = db.StringProperty(required=True) > > > > > owner = db.UserProperty(required=True) > > > > > latitudes = db.ListProperty(float, indexed=False) > > > > > longitudes = db.ListProperty(float, indexed=False) > > > > > altitudes = db.ListProperty(float, indexed=False) > > > > > heart_rates = db.ListProperty(int, indexed=False) > > > > > speeds = db.ListProperty(float, indexed=False) > > > > > > Each of the lists has just under 1500 entries (I only have 1 row at > > > > > the moment) > > > > > > You can see an example of what I do with this here: > > > > >http://mytrackviewer.appspot.com/trackView/ag1teXRyYWNrdmlld2Vycg0LEg. > > .. > > > > > > (I know, there are other places to put track data, I don't care, I'm > > > > > mostly just learning at this point) > > > > > > My fetch code looks like: > > > > > track_data = db.get(track_id) > > > > > if track_data and ( len(track_data.latitudes) == len > > > > > (track_data.longitudes) ): > > > > > logging.debug('fetched track data with %d lat/longs' % len > > > > > (track_data.latitudes)) > > > > > # blah blah blah, writes out stuff to generate the map from here. > > > > > > This log entry here though happens after ~750ms from the request log > > > > > entry. > > > > > > So my question is this: Is there some way to speed this up? > > > > > > I also tried splitting the Track common stuff from the Trackpoints, > > > > > and keeping all of the points in a separate table. That was a little > > > > > slower, so I'm guessing pulling 1 really big row with all the data is > > > > > faster than pulling 1500 individual rows, is that correct? > > > > > > Anything else I can try to speed up the query? would turning off the > > > > > validator help? I'm not sure what else to try. > > > > > > ok thanks > > > > > > -John > > > > -- > > > Nick Johnson, Developer Programs Engineer, App Engine > > -- > Nick Johnson, Developer Programs Engineer, App Engine --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
