You can certainly write to Memcache, but I don't think your application can tolerate any kind of volatility. Persistence is the price you have to pay. Fortunately, I think this can be done pretty cheaply. Just be aware of monotonically increasing indexes like timestamps: if you have an application with a high write rate that has a timestamp, this will cause the persistence unit storing the indexes to be unable to be autosplit easily across multiple hardware instances and you will take a performance hit. The solution here is, again, to shard the timestamp by prefixing a value to distribute the writes.
-- Ikai Lan Developer Programs Engineer, Google App Engine Blogger: http://googleappengine.blogspot.com Reddit: http://www.reddit.com/r/appengine Twitter: http://twitter.com/app_engine On Fri, Jan 14, 2011 at 6:06 AM, Richard Arrano <[email protected]>wrote: > I'm looking to make a silent-auction type of application where you > have 20-30 users bidding on an item at a time, with potentially > hundreds or thousands of auctions happening simultaneously. As soon as > a high bid is made, it updates this information and sends it via the > Channel API to the other users in the auction. I see two potential > difficulties: > > 1. The limit on updating an entity group about once per second - I > believe this can be solved with sharding bids amongst users in the > auction and querying all shards to find the maximum bid at any given > time, correct? > > 2. The nature of the auction lends itself to a heavy amount of > writing to the datastore - this itself eats up CPU and I’m trying to > figure out if it can be avoided. Is this just inevitable in this type > of application? Does it matter that I would only be only updating a > single IntegerProperty() in any given write? Is there some clever > solution that we can apply that avoids the hammering of the datastore? > > Any tips or suggestions would be appreciated. > > Thank you, > Richard > > -- > 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]<google-appengine%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- 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.
