On Sat, Aug 25, 2012 at 5:24 AM, Mos <[email protected]> wrote: > > Setting Max Pending Latency doesn't force requests to be in the pending > queue for the specified time. Please use Min Pending Latency instead. > > As you know my setting to "Min Pending Latency" was automatic. The > expectation is that GAE takes a reasonable default latency if it is > "automatic". > And you say: Every parallel request starts a new instance if it is > "automatic"? That' would be a "Min Pending Latency" of zero and not > "automatic". > > > If it doesn't work, try 2 min idle instances then > > Please check the responses of other user in this thread. This feature is > totally broken and can not be used.
> > >> And around the 16th august? > > Sigh... isn't it a waist of time? What is the reason you picked that > date? > > Did you see/studied my pictures from the first post of this thread? > The statistic shows that on this date the instance creation gets crazy. I > double checked it with the Pingdom reports. > Starting on this day there were even more downtimes. > > > So I'd say please try 2. If you still saw the user-facing loading > requests, you need more resident instance to eliminate the user-facing > loading requests. > > Again: As wrote in my post before that does not work. Check the responses > from Kristopher and Jeff on this thread. > > Yeah, it's very nice to hear concrete examples from Kristopher and Jeff, other than just saying "I've tried that, but it didn't work". > > > So what is your expected behavior and actual result? Nobody in our > team can do anything if you just keep saying "the setting that used to work > doesn't work anymore" without trying mu suggestion. > > I think my answer is clear at least for some points. 1) You'd better use > 'min pending latency' instead of 'max pending latency' to prevent new > instances to spin up as much as possible. 2) If you need longer instance > lives, set appropriate number of min idle instances. > > As I wrote: I tried different settings. As many other people in this group > as well. > Me and other people are reporting: The settings are broken! > It's very easy to reproduce. Please set up an application, send one > request per minute (or second), configure 1 or 2 or 3 min idle instances > and check what is happening. You will see that new instances are started > although resistant instances are available. > It's nice if we have a complete reproducible case. I've just started an experiment you mentioned. This time, it's just a helloworld application, and I set 1 min idle instances and 1 minutes cron. Presumably it will just work fine. Then I will try with slightly different condition. That way, I hope I can determine what kind of condition could be the culprit or not. What do you think? Can you provide some simple projects for that experiment? > Please take it serious and let somebody of the engineers check this! > (I'm one of the engineers btw) A reproducible case is always the best thing to get engineers' attention. Regards, -- Takashi > Cheers > Mos > > > On Fri, Aug 24, 2012 at 8:43 PM, Takashi Matsuo <[email protected]>wrote: > >> >> Hi Mos, >> >> On Sat, Aug 25, 2012 at 1:39 AM, Mos <[email protected]> wrote: >> >>> Hello Takashi, >>> >>> >>> > Actually there were almost 8 requests in a second. So App Engine >>> likely needed more than one instance at this particular moment. >>> >>> I thought this is why GAE has the concept of "pending-latency" (which >>> we discussed below). >>> Meaning: Incoming requests may wait up to 15 seconds before starting a >>> new instance. Therefore when 8 requests in one second occur that >>> should not mean that more instance needs to be started. Especially if >>> there is no other traffic in this minute, as seen in my example. >>> Otherwise it would be a very bad implementation: >>> Starting a new instance means around 30s waiting time. Serving 8 >>> parallel requests from one instance, would result in a maximum of >>> 8 seconds for the last request (assuming that each request takes around >>> 1 second). >>> There is no reason for this concrete example to fire up more instances >>> and let requests wait more then 30 seconds until a new instance is loaded. >>> >> >> Do you really read my e-mail? >> >> Setting Max Pending Latency doesn't force requests to be in the pending >> queue for the specified time. Please use Min Pending Latency instead. >> Can you try this first? If it doesn't work, try 2 min idle instances then. >> >> >>> >>> > ... here is what you've seen in the past weeks. >>> > >>> >* You have been almost always set 'Automatic-2' idle instance setting. >>> >* More than 3 weeks ago, number of loading requests were very few. >>> > * Recently you have seen more loading requests than before. >>> >>> That, right! To be even more concrete: At the 16. august the problems >>> got significant worse. Please check especially the time area from 16. >>> august until today. >>> >>> > First of all, it seems that you deployed 2 new versions on Aug 1 and >>> Aug 2. Can you describe what kind of changes in those versions? >>> >>> I checked it in our version control. As I wrote no related changes were >>> made! Just Html/Css stuff: >>> * One picture upload >>> * One html change >>> * One JavaScript change >>> * One css change >>> >>> >>> > And, to be fair, we didn't think of any change in our scheduler around >>> 3 weeks ago which can cause this issue. >>> >>> And around the 16th august? >> >> >> Sigh... isn't it a waist of time? What is the reason you picked that >> date? >> >> >>> >> >> >>> > More than 3 weeks before, those 2 idle instances might have had longer >>> lives than now, but it was not a concrete behavior. Please think this way: >>> you were just kind of lucky. >>> >>> That shouldn't be luck! If GAE is not able to start Java instances in >>> 5sec to 10 second, there needs be a guarantee that instances have longer >>> lives. Otherwise Java applications on GAE are unusable because user would >>> have a lot of 30seconds wait time (--> "failed requests"). (See also next >>> comment regarding resistant instances) >>> >>> >>> > If you want some instances always active, please set min idle >>> instances. >>> >>> I tried this some days ago. I had one resistant instance. But that >>> changed nothing. Instances get started and stopped as before. I assumed >>> that requests would go to the resistant instance first. But that was no the >>> case. Resistant instance was idle, but a dynamic instance got started and >>> the request waits 30sec. >> >> Please check other discussion on this list and issues that reported >>> similar observations. >>> >> >> So I'd say please try 2. If you still saw the user-facing loading >> requests, you need more resident instance to eliminate the user-facing >> loading requests. >> >> >>> >>> > As you can see, I'm still not convinced to believe that the scheduler >>> is misbehaving. I understand that you're having experiences which are bit >>> worse than 3 weeks ago, and understand your feeling that you want to tell >>> us 'fix it', but I'd say it's > >still something in the line of 'expected >>> behavior' at least for now. >>> > If you feel differently, please let me know. >>> >>> Yes I do feel differently (please see answers above). >>> >>> Please accept >>> http://code.google.com/p/googleappengine/issues/detail?id=8004 >>> >> >> So what is your expected behavior and actual result? Nobody in our >> team can do anything if you just keep saying "the setting that used to work >> doesn't work anymore" without trying mu suggestion. >> >> I think my answer is clear at least for some points. 1) You'd better use >> 'min pending latency' instead of 'max pending latency' to prevent new >> instances to spin up as much as possible. 2) If you need longer instance >> lives, set appropriate number of min idle instances. >> >> -- Takashi >> >> >>> >>> >>> Thanks >>> Mos >>> http://www.mosbase.com >>> >>> >>> On Fri, Aug 24, 2012 at 4:22 PM, Takashi Matsuo <[email protected]>wrote: >>> >>>> >>>> Hi Mos, >>>> >>>> On Fri, Aug 24, 2012 at 6:05 PM, Mos <[email protected]> wrote: >>>> >>>>> > A possible explanation could be that the traffic pattern had changed. >>>>> >>>>> No. It's the same. Check for example the Request/Seconds statistics of >>>>> my application for the last 30 days! >>>> >>>> >>>>> >> It's very obvious that one instance should be enough for my >>>>> application. And that was almost the case the last months! >>>>> > Actually it's not true. In particular, check this log: >>>>> >>>>> That's one expection where one client did 8 request in a minute (+ >>>>> one pingdom). Nothing else this minute. >>>>> In those exceptional cases it could be ok if a second instance starts. >>>>> (Nevertheless can't one instance not >>>>> handle 8 requests a minute?) >>>>> >>>> >>>> The issue here is not 8 requests in a minute. Actually there were >>>> almost 8 requests in a second. So App Engine likely needed more than one >>>> instance at this particular moment. Anyway, as you say, probably it's just >>>> a reason for one of the loading requests you're seeing, and this is not >>>> very important thing in this topic. >>>> >>>> It's kind of digressing, but at a first glance, the Requests/Seconds >>>> stat seems an appropriate data source to discuss how many instances are >>>> actually needed, but in fact, it's not. The real traffic is not spreading >>>> equally. >>>> >>>> >>>>> >>>>> As I described: Instances are started and stopped without reason, >>>>> even if less traffic per minute is available! >>>> >>>> >>>> Okay. As far as I understand, here is what you've seen in the past >>>> weeks. >>>> >>>> * You have been almost always set 'Automatic-2' idle instance setting. >>>> * More than 3 weeks ago, number of loading requests were very few. >>>> * Recently you have seen more loading requests than before. >>>> >>>> First of all, it seems that you deployed 2 new versions on Aug 1 and >>>> Aug 2. Can you describe what kind of changes in those versions? >>>> I'd like to make sure that there is no changes that can cause the >>>> scheduler/app server behaving differently. >>>> >>>> Especially, if you want me to escalate this issue to our engineering >>>> team, you should provide the exact information. You say 'My application is >>>> unchanged', but in fact you deployed the new version on that day when you >>>> described the issue started. I need to make sure that there is no big >>>> change which can cause something bad. >>>> >>>> And, to be fair, we didn't think of any change in our scheduler around >>>> 3 weeks ago which can cause this issue. >>>> >>>> Secondly, you're setting max idle instances = 2. It does not guarantee >>>> that you have always 2 instances. It just guarantees that we will never >>>> charge you for more than 2 idle instances at any time. >>>> >>>> More than 3 weeks before, those 2 idle instances might have had longer >>>> lives than now, but it was not a concrete behavior. Please think this way: >>>> you were just kind of lucky. Now, presumably one or two of those instances >>>> are occasionally killed for some reasons(there should be certain legitimate >>>> reasons, but those are something you don't need to care). >>>> >>>> If you want some instances always active, please set min idle >>>> instances. Certainly it will cost you a bit more, and you will loose the >>>> pending queue, but considering the access pattern of your app(no bursty >>>> traffic except for few access from the iPhone browser), I would recommend >>>> trying this setting in order to achieve what you want here. I'd recommend 2 >>>> idle instances in this case, but you should decide the number. >>>> >>>> >>>>> > * What is the purpose of max-pending-latency = 14.9 setting? >>>>> >>>>> " is high App Engine will allow requests to wait rather than start new >>>>> Instances to process them" >>>>> --> One attempt to stop GAE to create unnecessary instances. >>>>> >>>> >>>> I think you should set min pending latency instead of max pending >>>> latency if you want to prevent new instance to spin up. However, if you're >>>> going to set min idle instances, this setting will almost loose effect. If >>>> you don't want to set any min idle instances for whatever reason, please >>>> consider setting min pending latency instead of max pending latency. >>>> >>>> >>>>> >>>>> > * Can you try automatic-automatic for idle instances setting? >>>>> >>>>> I played around with this the last days and nothing changed. As I >>>>> wrote: I had those configuration for months and it worked fine 3-4 weeks >>>>> ago! >>>>> >>>> >>>>> > * What is the purpose of those pingdom check? What happens if you >>>>> stop that? >>>>> >>>>> To be alerted if GAE is down a again. "What happens if you stop that?" >>>>> --> I wouldn't be angry anymore because I wouldn't recognize downtime's of >>>>> my GAE application. ;) >>>>> >>>> >>>>> Please forward >>>>> http://code.google.com/p/googleappengine/issues/detail?id=8004 to >>>>> the relevant GAE deparment. >>>>> >>>> >>>> As you can see, I'm still not convinced to believe that the scheduler >>>> is misbehaving. I understand that you're having experiences which are bit >>>> worse than 3 weeks ago, and understand your feeling that you want to tell >>>> us 'fix it', but I'd say it's still something in the line of 'expected >>>> behavior' at least for now. >>>> >>>> If you feel differently, please let me know. >>>> >>>> Regards, >>>> >>>> -- Takashi >>>> >>>> >>>>> >>>>> Thanks! >>>>> >>>>> >>>>> On Fri, Aug 24, 2012 at 1:39 AM, Takashi Matsuo <[email protected]>wrote: >>>>> >>>>>> >>>>>> Hi Mos, >>>>>> >>>>>> On Thu, Aug 23, 2012 at 4:58 AM, Mos <[email protected]> wrote: >>>>>> >>>>>>> Does anybody else experience abnormal behavior of the >>>>>>> instance-scheduler the last three weeks (the last 7 days it got even >>>>>>> worse)? (Java / HRD) >>>>>>> Or does anybody has profound knowledge about it? >>>>>>> >>>>>>> Background: My application is unchanged for weeks, configuration >>>>>>> not changed and application's traffic is constant. >>>>>>> Traffic: One request per minute from Pingdom and around 200 >>>>>>> additional pageviews the day (== around 1500 pageviews the day). The >>>>>>> peek >>>>>>> is not more then 3-4 request per minute. >>>>>>> >>>>>> >>>>>> A possible explanation could be that the traffic pattern had changed. >>>>>> >>>>>> >>>>>>> >>>>>>> It's very obvious that one instance should be enough for my >>>>>>> application. And that was almost the case the last months! >>>>>>> >>>>>> >>>>>> Actually it's not true. In particular, check this log: >>>>>> >>>>>> https://appengine.google.com/logs?app_id=s~krisen-talk&version_id=1-0.360912144269287698&severity_level_override=1&severity_level=3&tz=Europe%2FBerlin&filter=&filter_type=regex&date_type=datetime&date=2012-08-23&time=23%3A57%3A00&limit=20&view=Search<https://appengine.google.com/logs?app_id=s%7Ekrisen-talk&version_id=1-0.360912144269287698&severity_level_override=1&severity_level=3&tz=Europe%2FBerlin&filter=&filter_type=regex&date_type=datetime&date=2012-08-23&time=23%3A57%3A00&limit=20&view=Search> >>>>>> >>>>>> You can see the iPhone client repeatedly requests your dynamic >>>>>> resources in a very short amount of time. Presumably it's due to some >>>>>> kind >>>>>> of 'prefetch' feature of that device. Are you aware of those accesses, >>>>>> and >>>>>> that this access pattern can cause a new instance starting? >>>>>> >>>>>> I don't think this is the only reason, but this can explain that some >>>>>> portion of your loading requests are expected behavior. >>>>>> >>>>>> Now I'd like to ask you some questions. >>>>>> >>>>>> >>>>>> * What is the purpose of max-pending-latency = 14.9 setting? >>>>>> * Can you try automatic-automatic for idle instances setting? >>>>>> * What is the purpose of those pingdom check? What happens if you >>>>>> stop that? >>>>>> >>>>>> >>>>>>> >>>>>>> But now GAE creates most of the time 3 instances, whereby on has a >>>>>>> long life-time for days and the other ones are restarted around >>>>>>> 10 to 30 times the day. >>>>>>> Because load request takes between 30s to 40s and requests are >>>>>>> waiting for loading instances, there are many request that >>>>>>> fail (Users and Pingdom agree: *A request that takes more then a >>>>>>> couple of seconds is a failed request!*) >>>>>>> >>>>>>> Please check the attached screenshots that show the behavior! >>>>>>> >>>>>>> Note: >>>>>>> - Killing instances manually did not help >>>>>>> - Idle Instances were ( Automatic – 2 ) . Changing it to whatever >>>>>>> didn't not change anything; e.g. like ( Automatic – 4 ) >>>>>>> >>>>>>> Thanks and Cheers >>>>>>> >>>>>>> Mos >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> 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. >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Takashi Matsuo | Developers Advocate | [email protected] >>>>>> >>>>>> -- >>>>>> 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. >>>>>> >>>>> >>>>> -- >>>>> 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. >>>>> >>>> >>>> >>>> >>>> -- >>>> Takashi Matsuo | Developers Advocate | [email protected] >>>> >>>> -- >>>> 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. >>>> >>> >>> -- >>> 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. >>> >> >> >> >> -- >> Takashi Matsuo | Developers Advocate | [email protected] >> >> -- >> 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. >> > > -- > 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. > -- Takashi Matsuo | Developers Advocate | [email protected] -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. 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