In my case, since I was getting the 20-second delay almost 100% of the time, setting countdown=1 was the answer. If you only see it happen every 20 or more request then of course it won't help.
In my case I also run all tasks on the backend. They're slightly more expensive per hour than frontends (due merely to the lower number of free hours) but in my case I more than make up for it with the fact that I have full control on the number of requests that will spin up, and I need to be able to control that number separately for tasks vs. users hitting my site. On Feb 5, 11:24 am, Carter <[email protected]> wrote: > We regularly but erratically see 10-20 minute delays in running push > queue tasks. > The tasks sit in the queue with ETA as high as 20 minutes *ago* > without any errors or retries. > > (the problem seems unrelated to queue settings since our Maximum Rate, > Enorced Rate and Maximum Concurrent all far exceed the queue's > throughput at the time of the delays) > > Any tips or clues on how to prevent this while still using push queues > without backends? > > On Feb 1, 9:03 pm, Robert Kluin <[email protected]> wrote: > > > > > > > > > Hey Dave, > > Hopefully Nick will be able to offer some insight into the cause of > > your issues. I'd guess it is something related to having very few > > tasks (one) in thequeue, and it not getting scheduled rapidly. > > > In your case, you could use pull queues to immediately fetch the > > nexttaskwhen finished with atask. Or even to fetch multiple tasks > > and do the work in parallel. Basically you'd have a backend that ran > > a loop (possibly initiated via a pushtask) that would lease atask, > > or tasks, from the pullqueue, do the work, delete those tasks, then > > repeat from the lease stage. The cool thing is that if you're, for > > example, using URL Fetch to pull data this might let you do it in > > parallel without increasing your costs much (if any). > > > Robert > > > On Wed, Feb 1, 2012 at 14:25, Dave Loomer <[email protected]> wrote: > > > Here are logs from three consecutivetaskexecutions over the past weekend, > > > with only identifying information removed. You'll see that eachtask > > > completes in a few milliseconds, but are 20 seconds apart (remember: I've > > > already checked myqueueconfigurations, nothing else is running on this > > > backend, and I later solved the problem by setting countdown=1 when adding > > > thetask). I don't see any pending latency mentioned. > > > > 0.1.0.2 - - [27/Jan/2012:18:33:20 -0800] 200 124 ms=10 cpu_ms=47 > > > api_cpu_ms=0 cpm_usd=0.000060 queue_name=overnight-tasks > > > task_name=15804554889304913211 instance=0 > > > 0.1.0.2 - - [27/Jan/2012:18:33:00 -0800] 200 124 ms=11 cpu_ms=0 > > > api_cpu_ms=0 > > > cpm_usd=0.000060 queue_name=overnight-tasks task_name=15804554889304912461 > > > instance=0 > > > 0.1.0.2 - - [27/Jan/2012:18:32:41 -0800] 200 124 ms=26 cpu_ms=0 > > > api_cpu_ms=0 > > > cpm_usd=0.000060 queue_name=overnight-tasks task_name=4499136807998063691 > > > instance=0 > > > > The 20 seconds seems to happen regardless of length oftask. Even though my > > > tasks mostly complete in a couple minutes, I do have cases where they take > > > several minutes, and I don't see a difference. Of course, when atasktakes > > > 5-10 minutes to complete, I'm going to notice and care about a 20-second > > >delaymuch less than when I'm trying to spin through a few tasks in a minute > > > (which is a real-world need for me as well). > > > > When reading up on pull queues a while back, I was a little confused about > > > where I would use them with my own backends. I definitely could see an > > > application for offloading work to an AWS Linux instance. But in either > > > case, could you explain why it might help? > > > > I saw you mention in a separate thread how M/S can perform differently > > > from > > > HRD even in cases where one wouldn't expect to see a difference. When I > > > get > > > around to it I'm going to create a tiny HRD app and run the same tests > > > through that. > > > > I also wonder if M/S could be responsible for frequent latencies in my > > > admin > > > console. Those have gotten more frequent and annoying the past couple of > > > months ... > > > > -- > > > 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/-/lbNQRQdSx0AJ. > > > > 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?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 [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?hl=en.
