Thank you, Ikai. Your comments were useful. I was fixated on "one object one entity". Following your advice, I collapsed the entities. Now, they are only handful.
One last doubt - how does writing to the disk work in the following scenario ? // transaction 1 // set two objects as properties // no doubt here entity.setUnindexedProperty( string1, object1 ) ; entity.setUnindexedProperty( string2, object2 ) ; put(). // transaction 2 // update object1 entity.setUnindexedProperty( string1, object1 ) ; put() ; App Engine stores bytes corresponding to object1 somewhere. I guess that string1 points to the disk location, enabling overwriting with updated bytes. My doubt is whether the second transaction forces writing bytes corresponding to object2 also to the disk, which is needless ? J.Ganesan On Nov 5, 3:56 am, "Ikai Lan (Google)" <ika...@google.com> wrote: > If all 4000 entites are in a single entity group, in theory you can do this > because it counts as a single transactional write. There's a maximum RPC > size of 11mb (implementation detail) so if you trip this, you're in some > trouble - the RPC size include not only the size of the entity but also the > size of all the indexes. > > The problem is that this is a bad design. App Engine charges for datastore > ops, so you're already using 4000 datastore write ops per request + > multiples for indexes. > > Instead, try to figure out how to can write the data in as few entities as > possible. I suspect you're still thinking relationally. You didn't answer > my question about what problem you're trying to solve. What are you > building? Why would 4000 writes be needed? Why can't all the data fit into > a single entity? > > -- > Ikai Lan > Developer Programs Engineer, Google App Engine > plus.ikailan.com | twitter.com/ikai > > On Fri, Nov 4, 2011 at 8:31 AM, J.Ganesan <j.gane...@datastoregwt.com>wrote: > > > > > > > > > Thank you, Gerald. I will look for alternative implementations if I > > can not call put() many times within a transaction. I am waiting for > > Ikai's comments. > > > J.Ganesan > > > On Nov 4, 11:02 am, Gerald Tan <woefulwab...@gmail.com> wrote: > > > If there is no need to reference the objects from outside the group, you > > > would probably find it a lot more efficient to store the while array > > > serialized as a byte array. > > > -- > > 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-java@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-java@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.
