Stephen thanks for the correction. Obviously I didn't try hard enough to paint a bleak picture :)
Richard I highly doubt that Twitter would be able to turn a tweet into something worth, say, $5. Remember that most tweets are rather mindless and of low quality. On Jan 10, 5:33 am, Stephen <[email protected]> wrote: > On Sun, Jan 8, 2012 at 8:12 AM, jon <[email protected]> wrote: > > > It's so expensive that the Relation Index Entity technique > > proposed by your own Brett Slatkin has become cost prohibitive. > > > If Twitter was built on GAE using Relation Index Entity, each tweet made > > by a popular user with 1 million followers would cost $1 each. > > I make it $2, as there is both an ascending and descending index on > the MessageIndex.receivers list property, even though you only need > one for equality matching. > > Actually, it's probably more like $3 as you need to get tweets in date > order, which will require a compound index on receivers and date. This > is looking pretty inefficient as $2 of the $3 cost is the overhead of > two unused single property indexes. > > > Let's say there are 1000 such users on Twitter. And if each one tweeted 10 > > times a day, the cost would be $10,000 a day! > > Apparently people tweet 250,000,000 times a day (2,900/sec), and the > average user has 136 followers. If twitter used the relatiion index > pattern on App Engine they might spend aprox. $105,000/day for write > opperations to store tweets, about $38 million per year (or > $1.20/sec). -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. 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.
