On Fri, Oct 21, 2011 at 12:29 PM, Philip <[email protected]> wrote: > I am converting an app to the high replication datastore. I have read > that each entity needs to have a parent in order to have consistent > reads in queries that return multiple entities. > > 1. If I use a cross group transaction does that make queries > immediately consistent even if added entities don't have parents > (ancestors)? >
No. > 2. Does using a parent (an ancestor query) speed up queries that > return multiple entities? > I'd like to know the answer to this too. I suspect yes. > 3. Should I just be using parents and regular (single entity group) > transactions instead of cross group transactions for performance > reasons? > It's one tool in the toolbox. G says an XG transaction with two groups takes twice as long as a single group transaction, so it halves your throughput. If either of these entities are under contention, this could be a significant issue. On the other hand, a single entity group can limit throughput in other ways. There's no one right answer here. Jeff -- 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.
