Write a MapReduce mapper to count everything and consolidate back to datastore. Schedule it meaningfully to your needs. On Sep 13, 2011 6:31 AM, "cghersi" <[email protected]> wrote: > Hi all, > > I need to collect some statistics on my entities in the datastore. > > As an example, I need to know how many objects of a kind I have, how > many objects with some properties setted to particular values, etc. > In usual relational DBMS I may use > SELECT COUNT(*) ... WHERE property=<some value> > or > SELECT MAX(*), ... GROUP BY property > etc. > But here I cannot see any of these structures. > > Moreover, I cannot take load all the objects in memory (e.g. using > pm.getExtent(MyCall.class, false)) as I have too much entities (more > than 100k). > > Do you know any trick to achieve my goal? > > Thank you very much! > Best > cghersi > > -- > You received this message because you are subscribed to the Google Groups "Google App Engine for Java" 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-java?hl=en. >
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