thanks Brandon I am thinking about it all the time. I wonder if you could help me with this particular case. I am selling an item in the auction, which has a time to expire and the price changes with each bid received. Lets say I have 50 users bidding in the same time. How could I use "Cache" here to calculate the item price on demand within a second using HRD? With MS I can do it easily without using non-reliable memcache. Or would you say that GAE is not suitable for that?
Thank you, Andrius On 7 December 2011 00:10, Brandon Wirtz <drak...@digerat.com> wrote: > I posted this logic once before but people only listen when they are > ranting.**** > > ** ** > > You can only change an entity once per second. You can however maintain a > data store “Cache” that will save you money, writes, and prevent you from > ever seeing write limits.**** > > ** ** > > By maintaining a Small DataStore of “Writes To commit” things you want to > write to data store permanently can be put in to a data store which you > increment the task on.**** > > ** ** > > When you do a Read from the datastore you check that the writes to commit > don’t supersede the data in the main data store.**** > > ** ** > > This will save you on indexing operations, and reduce your write > throttling and if done correctly can even move most of your reads to Memory > rather than DataStore.**** > > ** ** > > This will increase your number of reads. Which will increase your Costs > slightly over MS, but likely is better than having MS down or MS Read > OnlyTime.**** > > ** ** > > ** ** > > *From:* google-appengine@googlegroups.com [mailto: > google-appengine@googlegroups.com] *On Behalf Of *Andrius A > *Sent:* Tuesday, December 06, 2011 3:44 PM > *To:* google-appengine@googlegroups.com > *Subject:* Re: [google-appengine] Re: DeadlineExceeded errors haunting > every now and then**** > > ** ** > > In docs it says that HRD is more costly "*The High Replication Datastore > costs more due to the additional replication (see billing page for pricing > details). Due to the higher cost, we recommend High Replication Datastore > primarily for those developers building critical App Engine applications > that require the highest availability*". **** > > It also says "*queries on a single guestbook to be strongly consistent, > but also limits changes to the guestbook to 1 write per second (the > supported limit for entity groups). Therefore, writing to a single entity > group per guestbook is not ideal when high usage is expected. If your app > is likely to encounter heavy write usage, consider using another means. For > example, you can put recent posts in memcache with an expiration, and then > display a mix of recent posts from memcache and posts retrieved from the > datastore.*" **** > > How could we trust by putting data to memcache if we know it can be > evicted any time? To use HRD is not viable for applications which need > strong consistency for high rate of puts. At the moment MS is perfect what > it does but bloody thing keeps dying.. I can't believe there is no way to > improve MS and you are switching to HRD. In long term HRD can cause more > problems for applications parts were it wasn't aticipating to receive > higher rate of inserts, and having a limit of 1 write per second is > a disastrous.**** > > On 6 December 2011 23:29, Gregory D'alesandre <gr...@google.com> wrote:*** > * > > Hi Kenneth, **** > > ** ** > > We are planning to add blobstore migration at some point but it won't > likely be until the middle of Q1 at the earliest.**** > > ** ** > > Greg**** > > ** ** > > On Tue, Dec 6, 2011 at 3:27 PM, Kenneth <kennet...@aladdinschools.com> > wrote:**** > > Hi Greg, > > Can you give us some indication if the migration tool is ever going to > include blobstore migration? That's the only thing holding me back. I know > I can do it myself but I'd rather not. I see now that it has gone ga, have > you stuck a fork in it and called it done? > > Thanks**** > > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group.**** > > To view this discussion on the web visit > https://groups.google.com/d/msg/google-appengine/-/f7KzNP-pCuwJ.**** > > To post to this group, send email to google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > 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 google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > 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 google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > 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 google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > 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. 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