Java Appengine Standard environment takes long to respond /ah/warmup

[Sourav Chandra]

Hi,

In our java based standard appengine project, we have enabled warmup request, automatic scaling with min-idle-instance set to 1 while other scaling related options are default.

We have observed whenever we deploy any new version, /ah/warmup takes very long time ~10-20 seconds.

What could be the reason for this? Our deployed application size is ~25MB

Thanks,

Sourav

[Prakash A]

Dear Chandra,

From my perspective, warm-up can take such time, as it time taken during the instance creation, and NOT on the first request serving time. Now, coming to your question, why warm-up it takes 20 seconds, depends upon what you have coded in the warm-up. Its too ambitious to explain, without seeing the codes.

[Sourav Chandra]

There is no custom handler for warmup defined in our code. We are using jersey framework, could this be the reason

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[Nick (Cloud Platform Support)]

Hey Prakash,

I'm not familiar with the Jersey framework, but I can tell you this: if your app has a handler for /_ah/warmup, the log lines for those requests will show a status other than 404. If you don't have a handler for that route, then you will see these requests fail with 404. The fact that it takes so long for the request to finish seems to indicate that some work is being done by the instance when it receives that request, and although this is just a guess, I can guess you might see that these requests are returning 200 or 500 as their status code.

Let me know what the logs show, or if you have any further comments/questions. I'll be glad to assist!

Cheers,

Nick
Cloud Platform Community Support