Eduardo, Just out of curiosity, what happens if you use the low-level API?
http://code.google.com/appengine/docs/java/javadoc/com/google/appengine/api/datastore/package-summary.html I'm trying to figure out if this is an issue with JDO or the datastore on a "stuck" entity. Do you have the entity key? Can you look up the entity by key in the datastore viewer? -- Ikai Lan Developer Programs Engineer, Google App Engine plus.ikailan.com | twitter.com/ikai On Wed, Jul 27, 2011 at 5:23 AM, Eduardo Garcia Lopez <[email protected]>wrote: > Hi, > > I have been experiencing locks with task queues since last week, specially > when I use dynamic instances in my backends. During minutes, the CPU load > goes to 0% on all instances of a given backend that only processes task > queues; the queue keeps growing, but no single task is executed (and this > happens with as few tasks as 10). After some time (minutes), it starts > working again. The worst of all is that these locks are causing that some > operations on datastore timeout, so our application enters a catastrophic > spiral where everything starts to fail. > > The lock is produced always executing one specific task, in the first > instruction of the task, that is an access to Datastore. This access is just > a "getObjectById()" from an enrity kind that only has one entity! After 30 > seconds the query timeouts, and the task ends, but all other tasks keep > locked in the same instruction. Then, after some time, everything starts > working again. > > In my case I am using backends, and the backend that locks is dynamic with > 2 instances, 6 concurrent requests max. We do JDO access to datastore inside > the tasks, but I keep the JDO objects transient, to discard that the > problems are due to JDO locks. > > Eduardo. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/google-appengine-java/-/WEIRLR4jRUEJ. > 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. > -- 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.
