Google application engine Datastore - any alternatives to aggregate functions and group by?
The best way is to populate the summaries (aggregates) at the time of write. This way your reads will be faster, since they just read - at the cost of writes which will have to update the summaries if its likely to be effected by the write. 
Hopefully you will be reading more often than writing/updating summaries.
As is mentioned in the doc for google app engine, it does not support group by and other aggregation functions. Is there any alternatives to implement the same functionality?
I am working on a project where I need it on urgent basis, being a large database its not efficient to iterate the result set and then perform the logic.
Please suggest.
Thanks in advance.