On Nov 4, 5:08 pm, "Ian Bambury" <[EMAIL PROTECTED]> wrote: > Definitely. And SQL does it internally, creating and taking advantage of > design optimisations within the database application which came about after > millions of dollars and/or many hundreds of thousands of man hours spent by > the top people in the specialisation.
The query optimizations only make a big difference for complex queries. For simple queries, indexing and caching are the key. It's not clear that GAE's indexing or caching are deficient. Note that GAE does get to take advantage of a somewhat more relaxed consistency model. > > > If you > > > wanted to find out how many DVDs were never rented from a video rental > > > service over the last year, you'd have more than 1000 titles and even if > > you > > > didn't, you'd have to try to match them all up with all the rentals one > > at a > > > time. > > > Why? If each dvd has a unique key and a last rental time, it's > > trivial to write a query that will find the ones that weren't rented > > last year. > > If the last rental was yesterday, how does that help me work out if it was > rented in 2007? Or October to October. Keep two dates, or run the query two days ago. GAE does penalize unplanned queries, but so do tuned schemas in SQL systems. Queries that hit lots of records are going to be slow no matter what. > > > So it seems that it might be scalable in the sense that everyone in the > > > universe can look up the name of their cat at the same time, but it > > > doesn't > > > seem to scale well if your video rental shop has more than 1000 videos or > > > your company has more than 1000 order lines, etc. > > > > > > It looks like GAE might not be capable of being a real-world business > > > solution for anything with more than noddy requirements from what you say. > > > > > > In SQL you could do the whole thing, 10,000,000 records in one hit. It > > > might > > > take a moment or two, though, but it would do it. > > > > 10 million records at 100 bytes/record is 1 billion bytes. That > > doesn't happen in "a moment or two". > > You're obviously not used to British understatement. :-) It looked like a claim that SQL systems could access 10M records much faster than GAE. --~--~---------~--~----~------------~-------~--~----~ 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-appengine@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
