On 4 January 2011 21:57, nacho wrote: > I already know that in the datastore there is no aggregation > functions, and i also know about the 1000 entites fetch limit in a > query. > > But I would like to know how did you solve this problem. >
> > Do I need to create counters for every report that i need? Basically yes.You can either update them all at write time (and/or just defer it slightly using tasks, so that you write an entity; then setup a task, that will update the relevent counters) or use a map-reduce style process that runs though all the entities and updates/creates the counters in bulk. Could for example run this nightly or hourly. There are various libraries available for appengine to help with this. they are getting more advanced as time goes on. > > Let's say that i do this, and in one month i think that could be nice > to display another report and i dont have the counter for this, for > example, how many sms the webmaster receive by minute. Here, what can > i do? create another set of "counters" - a bulk job like mentioned above would probably created to initially create it, and then keep it uptodate moving forward using one of the options. In general AppEngine is designed for write-once, read-many. Ie slowly changing data displayed many more times than it updated. Its not so useful for highly dynamic OLAP style reports. ie ad-hoc reports infrequently viewed. -- 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.
