My understanding is that all writes within the same entity group are serialized. Hence a best practice is keep Entity Groups as small as possible. If there is contention between two simulatanous writes to the same Entity Group, one fails, and having retry logic here will help get that second write to succeed .... In my experience a high percentage of write retries succeed on 2nd or 3rd retry.... Hopefully this helps...
Thanks Enrique Perez Austin, Texas On Jan 28, 6:47 pm, Ugorji <[email protected]> wrote: > I want to put some entities in the same entity group as a parent. If > multiple users try to create child entities at the same time, will > their put requests all lock on the parent entity and get executed in > sequence (even though I am not making any changes to the parent? and > the parent does not hold references to the children). I would hope > not, but want some clarity on this. > > If their put requests get run one at a time, will I have to > continually retry? I read somewhere that App Engine automatically > retries non-transactional requests on failures. However, I then read > here that we should retry our requests as is typical where optimistic > concurrency is > used.http://code.google.com/appengine/docs/java/datastore/transactions.htm... > > What are the rules on when a retry is needed? Are they needed anytime > I try to create a child entity without affecting the parent? -- 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 [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-java?hl=en.
