Target Response flow is taking huge time to process!

[dilipkn27]

Apigee guru's,

Need your insight on below issue. Seems to be Apigee has a bug in target response flow.

here is my use case, i am trying to invoke a rest service hosted on external vendor.

Successfully able to connect external vendor and receive the response But the issue is "Target Response Flow" which is taking huge time - 380ms(it is varying 61-380ms) I haven't configured anything in target endpoint(pre/post flow) but i have configure MLP in PostClientFlow.

Could you please let me know why it is taking huge time? is it a bug in apigee?

[dchiesa1]

It's impossible to say why. Based on the information you provided, I can say the behavior you're observing is not likely to be the result of a bug in Apigee Edge. It's more likely due to a configuration detail that is under your control.

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The first thing I would check is the time required to process the message. If the response is very large, and if the target is "far away" from Apigee Edge on the internet, then it can take a long time to transmit the response. Data on the internet travels at the speed of light along fiber links, but if it needs to be routed among different network links, it will slow down.

The speed of light is fast, but it is not infinite. As an illustration, Verizon publishes its network transit latency on various links: https://enterprise.verizon.com/terms/latency/

From NYC to London, it takes about 90-100ms. From Hong Kong to the US, it can take 160ms. This is for just one data packet. If you have a large payload of data, transmitting the data can take a multiple of that latency. More if the links are busy and noisy.

To sum it up, the latency you are observing may be as expected, depending on where your target is, and where your Apigee Edge proxy is, physically. Each system that runs "in the cloud" actually does run "on a computer" somewhere on the earth and you need to consider distances between communicating endpoints in figuring your expectations as to latency.

Apigee Edge SaaS has network presence in various regions around the globe. I can't say where your Apigee Edge proxy is running, but if you have a commercial license for Apigee Edge SaaS, then you should know this. You can ask Apigee to provision your Apigee Edge tenant so that your proxies run in a region that is "closer" to your targets or clients.

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After the network, the next thing I would look into is the behavior of the target endpoint. If it begins sending data and then delays for a bit, then resumes sending data, this obviously this introduces latency into the response. Even if the target is in the same region, which would minimize network transit latency, the app itself may introduce response latency.

Those are the two big factors you should check.