search

Azure / azure-functions-host

The host/runtime that powers Azure Functions
https://functions.azure.com
MIT License
1.91k stars 435 forks source link

HttpTrigger Function response unexpectedly slow #2327

Open JamesDuggan opened 6 years ago

JamesDuggan commented 6 years ago

HttpTrigger function that normally returns sub second, either hangs or takes minutes to respond.

Investigative information

Please provide the following:

Repro steps

behaviour was random and occurring regularly on 2018-01-18 from 20:00

Expected behavior

Sub second response

brettsam commented 6 years ago

I do see a lot of timeouts around this time for you. Is it possible a downstream service you're interacting with in your function was having issues or was slow?

JamesDuggan commented 6 years ago

I would say no. The function is very simple. Write n EventHub events based on input n. Typically n is in the range of 10-100 and the function completed in sub 500ms. On the date in question the performance simply dropped of the cliff. I have also logged issue #2328 which is for the same period. It may or may not be related.

sadgit commented 5 years ago

I am also having serious performance issues. My issue is that a function that can run as quickly as 25ms and with a 50% @ 250ms (10x) - has a significant number of executions in the range up to 7 secs (95% @ 5.4sec).

This frequent slow processing appears to be on a staggering thread - rather than CPU or Memory loading.

One of the functions is a fan-out request to 6 NotificationHubs on parallel threads. All code is async. We have a ServiceBus micro-services implementation and this variability has only occurred since porting from V1 to V2.