Hi Hugo, Thanks for the comments.
But its not moot. The element in appengine-web.xml is obligatory, but can be set to false. Current production environment respects it. I have done many tests to verify that with overlapped requests and the changes in behaviour when changing that setting. Point taken about multiple parallel instances and ds/mc. I thought I discussed that but maybe left it out in final version - not "multi-threading within a VM" or affected by setting in question though.....we could call that "instance-safe" :-) Thanks Andrew On 25 Sep 2012 18:52, "Hugo Visser" <botte...@gmail.com> wrote: > Hi Andrew, > > To me, the whole point is kinda moot, since threadsafe is a required > setting for Java apps (which is a good thing). > > Also, the points that you raise in the post are not different from the > gotcha's as they are present in a "normal" Java servlet stack. There's not > much App Engine specific in there. > > The statements like "static initializers are safe" are technically not > correct; while it's true for a single instance running multiple threads, > your app will still run on multiple instances. So if you are doing > something funky in a static initializer (like writing to the datastore) > there's still the possibility of race conditions or data corruption. > Same holds true for writing to memcache and the data store that you > describe in the post: even if your app is single threaded, a production app > will run on multiple instances which could all concurrently write to the > same entity or memcache entry. > > I hope you find this useful :) > > Hugo > > On Monday, September 24, 2012 2:41:25 PM UTC+2, Andrew Mackenzie wrote: >> >> I have published an analysis of using multi-threading for GAE/J here >> http://devcon5.blogspot.com for a project I am working on. >> >> I would very much appreciate any comments, corrections, ommissions or >> additional questions I should cover. >> >> 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/-/lHqF2_MQTAIJ. > 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.
