【发布时间】：2016-11-11 22:57:32
【问题描述】：
我有一个类似 Instagram 的应用程序，用户可以在其中将图像提交到公共供稿。我正在检查服务器日志，发现偶尔会出现响应时间较长的 POST 请求。
日志：
437 <158>1 2016-11-06T15:21:26.974333+00:00 heroku router - - at=info method=PUT path="/api/users/678499625650172?ciOiJIUzI1NiJ9.eyJ1aWQiOiI2Nzg0OTk2MjU2NTAxNzIifQ.SwzWCphNtbW_WciaBgKieXbSLNrznN1EfD7HGZ4j-bw" host=website.com request_id=e77a92b4-bebb-40ad-9476-9d94071b1b9f" dyno=web.1 connect=0ms service=7623ms status=200 bytes=1300
439 <158>1 2016-11-06T15:45:55.783260+00:00 heroku router - - at=info method=PUT path="/api/users/1770954736492550?GciOiJIUzI1NiJ9.eyJ1aWQiOiIxNzcwOTU0NzM2NDkyNTUwIn0.HwT1Di67QLhaZD2jOnV-HMOyqoZUsgOj1PMwkW-JVzA" host=website.com request_id=27b9dfd6-5eea-4e73-a148-bc43149b59ea" dyno=web.1 connect=0ms service=7524ms status=200 bytes=2154
294 <158>1 2016-11-06T15:52:21.479434+00:00 heroku router - - at=info method=POST path="/api/posts" host=website.com request_id=5125b25f-2665-4ce0-9e7c-9410fcfe66b5" dyno=web.1 connect=1ms service=8369ms status=200 bytes=745
294 <158>1 2016-11-06T15:56:47.161275+00:00 heroku router - - at=info method=POST path="/api/posts" host=website.com request_id=59468957-e075-486a-98c4-47f784c3f3b4" dyno=web.1 connect=0ms service=7777ms status=200 bytes=751
294 <158>1 2016-11-06T16:19:47.559217+00:00 heroku router - - at=info method=POST path="/api/posts" host=website.com request_id=b59bee23-1020-4f45-a08f-ba0fd6c6c02c" dyno=web.1 connect=0ms service=6762ms status=200 bytes=936
438 <158>1 2016-11-06T16:24:49.776264+00:00 heroku router - - at=info method=PUT path="/api/users/1444768362206977?GciOiJIUzI1NiJ9.eyJ1aWQiOiIxNDQ0NzY4MzYyMjA2OTc3In0.zYJyQeoileWWYuge8p3rwVAJdgkHtuPyx8wepqjfc7o" host=website.com request_id=602176e6-93d6-485c-a192-2562301d34a4 dyno=web.1 connect=1ms service=5986ms status=200 bytes=2170
293 <158>1 2016-11-06T16:37:59.811535+00:00 heroku router - - at=info method=POST path="/api/posts" host=website.com request_id=aca06dff-8975-44e9-a88b-7b3d2436b529 dyno=web.1 connect=0ms service=6190ms status=200 bytes=809
438 <158>1 2016-11-06T17:18:00.812751+00:00 heroku router - - at=info method=PUT path="/api/users/1037160479734847?GciOiJIUzI1NiJ9.eyJ1aWQiOiIxMDM3MTYwNDc5NzM0ODQ3In0.FV5KynHyOQfn7DvGRm3YJ7DK9KHt_24wnzlUUjLQyvs" host=website.com request_id=fb64c800-d10d-4350-ae35-9f373980d4a2dyno=web.1 connect=1ms service=29888ms status=200 bytes=2157
436 <158>1 2016-11-06T20:38:14.512715+00:00 heroku router - - at=info method=PUT path="/api/users/367712420227701?ciOiJIUzI1NiJ9.eyJ1aWQiOiIzNjc3MTI0MjAyMjc3MDEifQ.fF_2kVeVNJWkbldACd6LDdgHFWQUTLaj3gt5zU5adMw" host=website.com request_id=669a7c34-1d73-49dc-89f0-545c025a27addyno=web.1 connect=1ms service=70156ms status=200 bytes=1584
292 <158>1 2016-11-06T22:19:33.247574+00:00 heroku router - - at=info method=POST path="/api/posts" host=website.com request_id=8b772cd0-ce91-4180-a0e8-980045697e1dyno=web.1 connect=0ms service=21110ms status=200 bytes=747
477 <158>1 2016-11-06T23:20:35.320688+00:00 heroku router - - at=warning code=H28 desc="Client Connection Idle" method=PUT path="/api/users/704013223107561?host=website.com request_id=caff0a18-c80c-4a4f-9e47-d0ee94134336 dyno=web.1 connect=0ms service=55054ms status=499 bytes=71
428 <158>1 2016-11-07T01:48:49.357164+00:00 heroku router - - at=info method=GET path="/api/posts?host=website.com request_id=13299069-adf1-45cb-b872-836b8ee958c9 dyno=web.1 connect=2ms service=7505ms status=200 bytes=29626
294 <158>1 2016-11-07T01:51:02.673770+00:00 heroku router - - at=info method=POST path="/api/posts" host=website.com request_id=548d556c-6bcb-4e4c-aac8-30208babeb5e dyno=web.1 connect=0ms service=40072ms status=200 bytes=743
428 <158>1 2016-11-07T02:01:54.350464+00:00 heroku router - - at=info method=GET path="/api/posts?host=website.com request_id=d6dc9f4f-11b4-4bbe-86ce-3c955b7c4850 dyno=web.1 connect=0ms service=5034ms status=200 bytes=28331
427 <158>1 2016-11-07T02:02:41.680396+00:00 heroku router - - at=info method=GET path="/api/posts?host=website.com request_id=ee08a0ac-a737-4f06-a25d-cfcc7bdfa949no=web.1 connect=0ms service=5747ms status=200 bytes=28432
479 <158>1 2016-11-07T02:25:18.336787+00:00 heroku router - - at=warning code=H28 desc="Client Connection Idle" method=PUT path="/api/users/1800664756874454?host=website.com request_id=a44038a2-0134-47df-94be-69e7dd2e4a90 dyno=web.1 connect=0ms service=310903ms status=499 bytes=0
当用户以多部分形式发送带有文本正文和图像的POST请求时，服务器将图像上传到S3并将帖子保存到DB，并响应用户。我怀疑当许多用户同时上传时，服务器进程正忙于将图像文件上传到 Amazon S3 并导致如此高的响应时间。不过，这只是我的猜测。
当人们提交帖子时，我是否应该先将帖子保存到数据库中而不使用图像，然后将图像上传到后台作业中并更新帖子？还是有其他原因导致响应时间如此之长？
更新：新遗迹报告
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标签： ruby-on-rails performance amazon-s3