Hi Everyone, I've been trying for the past while to get our relatively simple JDO based site to run at a reasonable speed, but I'm failing and I'd love any suggestions. I'll describe it as succinctly as possible to hopefully keep your interest :)
* The basic structure is a User -> Order -> Line items type structure. * The main query performed is "Orders for a user." * A user usually has around 10 orders, each order has under 100 line items. * The Order -> Items relationship is done as a One-to-many owned relationship. My problem is that the basic request the site handles: "Get all orders for a user and do something based on the line items" is very slow. In real response time, my average is now 1.5 seconds, and some of the users are seeing 20 second response times. Clearly not ok. What appears to be slow, after profiling with the new app stats tool is that each line item is getting loaded as it's used (lazy loading), which works great in some cases but terrible in this case since each item takes 20-30ms to load. I have tried: * Moving items into the default fetch group for orders, seems to have no effect (may not even be possible due to limitations of joins) * Level 2 caching with memcache - not much effect either since only the individual line items are cached, not the whole List, so we still pay a price in round trip to the cache on each line item. * A sort of wacky cache that I wrote on top of the JDO managed relationship to cache the whole collection. This went poorly and resulted in odd data inconsistencies, probably because I did something wrong but the whole thing felt wrong. So my question is - what am I doing wrong? What's the best/standard way to represent a Master -> Detail type relationship, where the total items for a user will be relatively small but requests need to work with a fair number of them. Thanks for any suggestions, I'd be happy to answer any questions if what I've written isn't clear. Matt -- 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.
