The biggest question is why would you want to do this? >From the low-level api perspective, you can't have a list property with more than 5k items. But maybe JDO models this list as a proxy to a query. When you try to load that proxy it's going to load all 5m items out of the datastore and you are going to wait a long time. It will not complete in reasonable time scales - it might take over an hour, and unless you're running in a backend you will certainly blow the request time limit. And even there you'll blow the amount of time for a single query to run, which is something like one minute.
So no, you can't do this if you actually plan to load the list directly. But maybe you're just using this to model the data and plan to use filtering operations for queries, in which case you can do that as long as you never load the whole set. The real question is not whether you can store the data (presumably there's a way to make it possible) but whether you can execute whatever queries you have min mind. You should post examples of those. FWIW, it sounds like a terrible idea. Store them all in separate EG's and use normal queries to access them. Jeff On Fri, Feb 17, 2012 at 10:07 AM, hendrix.jason <hendrix.ja...@gmail.com>wrote: > Well, I plan to write in batches of 1,000. So a million items would > take 1,000 batch writes. In the worst case scenario of 1 write per > second that's about 17 minutes. That's acceptable for a once nightly > job. > > On Feb 17, 2:31 am, Cyrille Vincey <cvin...@qunb.com> wrote: > > Forget about this way : even if this having millions of children > > entities for one ancestor is theoretically feasible, you'll hit a > > write performance issue when you generate those entities : only 1 > > write / second in one given entity group (ancestor). > > > > On 17 fév, 03:16, "hendrix.jason" <hendrix.ja...@gmail.com> wrote: > > > > > > > > > > > > > > > > > If I have a @PersistenceCapable class that contains a List of another > > > @PersistenceCapable class, and that List is millions of items in size, > > > is that OK? > > > > > Does that exceed a maximum for Java's List size? > > > > > What is the best way for a parent to have millions of children and > > > still have it easy to add new ones without loading tons of data in to > > > memory? > > -- > 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.
