An entity group is a group of objects, not classes. If Article#1237 and its comments are in a single entity group, then yes you'll have trouble with more 100 comments per second. Simple solution: Don't put the comments in the article's entity group.
Jeff On Fri, Dec 11, 2009 at 12:31 AM, Nickolas Daskalou <n...@daskalou.com> wrote: > After reading these two articles: > > Avoiding datastore contention: > http://code.google.com/appengine/articles/scaling/contention.html > Sharding counters: > http://code.google.com/appengine/articles/sharding_counters.html > > I'm a little confused at to what causes datastore contention, and how > to design around this. > > The Avoiding datastore contention article states that datastore > contention "occurs when a single entity or entity group is updated too > rapidly". Yet the Sharding counters article seems to suggest that you > can rapidly update entities of the same kind (and hence entity group), > as long as they have different key names. > > Which it is? > > For example, if I am expecting 100 comments/second to an article I've > written (let's assume I'm a really good writer), and the Comment class > is its own entity group, can I safely put() all comments into the > datastore as they arrive using this Comment class, or am I better off > sharding them into separate classes (eg. Comment1, Comment2, ..., > CommentN) so that the comments are distributed across N entity groups? > > -- > > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to google-appeng...@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appeng...@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
