有时 503 服务在同时 API 调用上不可用。 NodeJS 与 mongoDB

Question

We are working on a mobile application, Being a mobile developer Im lack of server knowledge.

Some custom apis are made to do some longer operations such as retrieving orders of customer from the db and eliminating the invalid records and returning the remaining as response back.

When the same custom API is called multiple times parallelly i get 503 service unavailable error sometimes. But when I call only once at a time the API seems working fine.

But some other apis which does simple operations work very well even if they called 100 times simultaneously. So i hope there is no problem with server hardware resources.

What can be the issue, Just trying to understand. While I was researching on this issue I came to know these things..

Redis, Queue Systems, MongoDB Queue

Is this issue is related to the above things or can it be related to the Load balancer, NGINX or it's Just the way how the custom API is written or could it be the server resources?

I just found similar question but couldn't find any answers.

NodeJS app with Apache2 sometimes returns 503 Server Unavailable

Please help!!

Thanks in advance:)

Answer 1

I checked the log with server guys support, It turns out the problem was returning call back in incorrect place.

The actual error getting thrown was error callback was already called. And the server was restarting.

We started fixing all the apis one by one and the problem seems went off