Azure API管理延迟超过5秒

Question

我们正在使用API​​管理来执行一个始终运行的功能应用程序，该应用程序又调用了Azure搜索。功能应用程序会在100毫秒（通常情况下）内响应，但是API管理会间歇性地花费3到8秒来处理。我遍历了跟踪，发现延迟始终在API管理处理结果的后端步骤中（下面的后端示例跟踪）。在这种情况下，返回的数据为664字节。有谁知道是什么原因造成的，更重要的是，如何消除这种延迟？

Azure API管理实例，功能应用程序和Azure搜索都在同一区域。

"backend": [
{
    "source": "forward-request",
    "timestamp": "2018-10-11T13:33:54.0578250Z",
    "elapsed": "00:00:00.0005890",
    "data": {
        "message": "Request is being forwarded to the backend service. Timeout set to 300 seconds",
        "request": {
            "method": "GET",
            "url": "https://ommitted.azurewebsites.net/api/HollanderSearch/?hollander=125-222L&websiteId=1&retrieveAllProductNames=false&onlyRetrieveProductNames=true&numRecsToRetrieve  =25&code=%2Fxu1iz0EimDFnOUvhDVaM4ZejfaW7umV3somaIDCeWJYI5RMIfNnNg%3D%3D&keyword=125-222L",
            "headers": [
                {
                    "name": "Ocp-Apim-Subscription-Key",
                    "value": "ommitted"
                },
                {
                    "name": "Postman-Token",
                    "value": "9e809f11-6e63-4422-8c3f-d61962cec6ac"
                },
                {
                    "name": "Cache-Control",
                    "value": "no-cache"
                },
                {
                    "name": "Accept",
                    "value": "*/*"
                },
                {
                    "name": "Accept-Encoding",
                    "value": "gzip,deflate"
                },
                {
                    "name": "User-Agent",
                    "value": "PostmanRuntime/7.3.0"
                },
                {
                    "name": "X-Forwarded-For",
                    "value": "omitted"
                }
            ]
        }
    }
},
{
    "source": "forward-request",
    "timestamp": "2018-10-11T13:33:59.6717259Z",
    "elapsed": "00:00:05.6045857",
    "data": {
        "response": {
            "status": {
                "code": 200,
                "reason": "OK"
            },
            "headers": [
                {
                    "name": "Pragma",
                    "value": "no-cache"
                },
                {
                    "name": "Transfer-Encoding",
                    "value": "chunked"
                },
                {
                    "name": "Content-Encoding",
                    "value": "gzip"
                },
                {
                    "name": "Vary",
                    "value": "Accept-Encoding"
                },
                {
                    "name": "Cache-Control",
                    "value": "no-cache"
                },
                {
                    "name": "Content-Type",
                    "value": "application/json; charset=utf-8"
                },
                {
                    "name": "Date",
                    "value": "Thu, 11 Oct 2018 13:33:59 GMT"
                },
                {
                    "name": "Expires",
                    "value": "-1"
                },
                {
                    "name": "Set-Cookie",
                    "value": "ARRAffinity=8065e5ea6c0774f598f30cd38416a122cd6afe1af34a15c7f6430e1a0fe9924c;Path=/;HttpOnly;Domain=omitted-dev.azurewebsites.net"
                },
                {
                    "name": "Server",
                    "value": "Microsoft-IIS/10.0"
                },
                {
                    "name": "X-Powered-By",
                    "value": "ASP.NET"
                }
            ]
        }
    }
},
{
    "source": "decompressor",
    "timestamp": "2018-10-11T13:33:59.6717259Z",
    "elapsed": "00:00:05.6045976",
    "data": "Content-Encoding header with value `gzip` detected in message headers. Content re-compression may require to correctly apply content modification policies."
}

]