Hi there, I'm developing an application that requires me to create lots of child entities within the same entity group transactionally. The tasks being generated to do this come in unpredictable bursts - sometimes 100/s for an entity group. This is clearly exceeding the 1/s limit for transaction contention and causing some real problems for my poor application.
I need a way to either batch the required updates for each entity group so I can run through them serially or otherwise schedule each update to run on a 1/s basis. The ideas I've come up with so far: 1. Use some kind of memcache'd timestamp or counter to schedule or throttle the updates. My question is how to do this in a way that will work with 100's of tasks hungrily looking for their time slot? Should I do a CAS for when the last task was scheduled (would this even work with the contention we're talking about?) or can I use an atomic operation like incr() somehow? 2. Store the work items somewhere and then at some later time query for the work items for an entity group and create the children in serial. I'd like to avoid this, if possible, as it creates many other headaches. My application is already using the taskqueue to great effect. This really seems like a queue problem - if only there was some kind of dynamic subqueue where I could add tasks with a 'namespace' of the entity group. Then entity groups could run in parallel, but the entity group items would still be in serial. Does something like that exist? Any suggestions or experiences on how I can work around this would be appreciated. Many thanks, Nikolaj -- 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.
