>From my experience : I do NOT expect a better write performance than 1 transaction/second when creating entities inside one given entity group (with 1 entity created in each transaction).
In your case : if dataset creation is an offline process, you can rely on entity groups and parent/child data modelling, no matter how many child entities you want to store. But you will have to expect high datastore contention level. My suggestion : in your data model design, only use parent/child design when transactional features are REALLY required. If transactional requirement are not so high, prefer to break your data model into smaller entity groups. On 21/10/10 17:00, "nicanor.babula" <nicanor.bab...@gmail.com> wrote: >Thank you all for your responses. >@alesj >No, I am not confusing entity "group" with the actual entities stored >in the datastore. > >@Ian Marshall >Actually no, because I already did that kind of analysis. > >I have to use transactions in order to maintain data consistency and >therefore I have to define the right entity groups. I already thought >of a solution, just that I have read in the docs that is not >recommended to put too many entities in an entity group. So: What is >the number of child entities a parent entity can have, past which the >datastore becomes slow? Hundreds? Thousands? Millions? >I also understand that all entities in an entity group are stored on >the same node of the datastore's distributed system and therefore I >understand that if the number of entities an entity group has is too >big, the queries will become slow, because will be processed by a >single node. Right? >Again: Which is that number? > >Thanks and sorry if I bored you with my long email. ;) > > >On 21 Ott, 14:59, Ian Marshall <ianmarshall...@gmail.com> wrote: >> How about my comments below? >> >> http://www.google.com/url?url=http://groups.google.com/g/f907f736/t/f... >> >> Do they help you? >> >> On Oct 20, 6:39 pm, "nicanor.babula" <nicanor.bab...@gmail.com> wrote: >> >> >> >> > Hi everbody, >> >> > I have a question regarding the datastore best-practices. >> >> > The appengine's official documentation says that is not a good >> > practice to put too many entities in the same entity group. What does >> > "too many" mean in this case? Hundreds? Thousands? Milions? >> >> > Thanks in advance, >> > Cristian Babula. > >-- >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 >google-appengine-j...@googlegroups.com. >To unsubscribe from this group, send email to >google-appengine-java+unsubscr...@googlegroups.com. >For more options, visit this group at >http://groups.google.com/group/google-appengine-java?hl=en. > -- 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 google-appengine-j...@googlegroups.com. To unsubscribe from this group, send email to google-appengine-java+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
