发送中等大小的 JSON 时，为什么在 heroku dev-dyno 上出现 H28/“客户端连接空闲”？

Question

我Meteor在 heroku dev dyno 上有一个简单的应用程序，我注意到如果POSTed 请求上的 JSON 有效负载有点大（在这种情况下）Content-Length: 2161），连接将超时。

只有每 6-7 个请求通过， 即使我是唯一的用户也只会。

卷曲请求：

curl -X POST -H 'Content-Type: application/json; charset=UTF-8' http://APP_SUBDOMAIN.herokuapp.com/api/cars/ --data '{"_id":"car-data-10","crlData":{"latitude":48.17375412849221,"longitude":11.531698666512966,"mapIcon":"/imgs/car_icon_white.png","mapIconSelected":"/imgs/car_icon_red.png","positionInitialized":true,"rotation":90.0},"description":"Das Fahrzeug ist in einem sehr guten Zustand. Letzter Service wurde bei 81000km gemacht. \nFahrzeug ist achtfach bereift.\nWinterreifen,TUV, und die Batterie sind neu. Ausserdem sind alle Bremsen neu.\n\nDie abnehmbare Anhangerkupplung wurde nur fur einen Fahrradtrager verwendet.\n\nWeitere Sonderaustattungen: Dynaudio Soundsystem, Berg An - und Abfahrhilfe, automatisches Auf -und Abblendlicht, Coming Leaving Home, Innenraumbeleuchtung dimmbar, Auf -und Abblendlicht Xenon, Tagfahrlicht, selbslenkendes Einparken, dunkler Innenraumhimmel.","features":{"exterior":["Alloy wheels","Electric side mirror","Trailer coupling"],"extras":["Full Service History","Non-smoker vehicle"],"interior":["Bluetooth","CD player","Central locking","Climatisation (Automatic air conditioning)","Electric heated seats","Electric seat adjustment","Electric windows","Hands-free kit","MP3 interface","Multifunction steering wheel","On-board computer","Parking sensors (Front, Rear, Self-steering systems)","Power Assisted Steering","Sport seats","Tuner/radio"],"safety":["ABS","Adaptive lighting","Airbags (Front and Side and More Airbags)","Daytime running lights","ESP","Fog lamp","Immobilizer","Light sensor","Rain sensor","Xenon headlights"]},"images":["/dealerships/bmw/view_files/jpg/default_3.jpg"],"make":"BMW","model":"330d xDrive Touring","price":"16500","technicalData":{"extended":{"co2_emissions_combined":null,"colour":null,"cubic_capacity":null,"door_count":null,"emission_class":null,"emissions_sticker":null,"fuel_consumption_combined":null,"fuel_consumption_extra_urban":null,"fuel_consumption_urban":null,"hu":null,"interior_colour":null,"interior_design":null,"number_of_seats":null},"main":{"category":"saloon, used vehicle","first_registration":"fr 11/2010","fuel_type":"petrol (e10-enabled)","gearbox":"manual gearbox","power":"155 kw (211 ps)"}},"title":"BMW 330d xDrive Touring","makeAndModel":"BMW 330d xDrive Touring"}'

服务器上的错误：

at=warning code=H28 desc="Client Connection Idle" method=POST path="/api/cars/" host=APP_SUBDOMAIN.herokuapp.com request_id=b3a75450-8fa2-4c71-a0b5-526b918dade2 fwd="IP_ADDRESS" dyno=web.1 connect=0ms service=55083ms status=499 bytes=0
2016-10-13T21:22:58.286627+00:00 app[web.1]: Error: request aborted

另一方面，内容如

 --data '{"_id":"car-data-10","crlData":{"latitude":48.17375412849221,"longitude":11.531698666512966,"mapIcon":"/imgs/car_icon_white.png","mapIconSelected":"/imgs/car_icon_red.png","positionInitialized":true,"rotation":90.0}}'

的 Content-Length: 217经历，每次没有问题。

本地一切运行顺利。

在我正在开发的这个演示应用程序中，我减少了请求负载，但是

...我的问题是：

是否有任何我不知道的限制可能导致超时？

附注。在服务器端，我在数据库中做了一个简单的保存