Troubleshooting of slow website login

Troubleshooting of slow website login

When I arrived at the company yesterday morning, I sent an email saying that some users reported that it was slow to log on to site A. After logging on, the operation was normal, so the network and server pressure could be ruled out.

The next step is to check whether the database and cache have become bottlenecks and there is no such thing as A result. After all, Station A is already A marginalized product and is not maintained on A regular basis.

Slow logon is caused by database bottlenecks, cache problems, program code problems, high concurrency, high application server load, and calling third-party interfaces.

The other reasons can be directly discharged, so there are only two suspicious issues in the program code and the call to third-party interfaces. In order to eliminate the suspicion of the former, I deployed another environment on the test server and rolled back the code to the version N months ago, but the problem persists. There is only one reason left: A third-party interface is called during login on Site. But Station A has not been maintained for A long time, and the original developer has left the company. It is unclear which external interfaces are called.

Instead, I had to log on to the server to capture packets and try to analyze whether the packet contained the call to other URLs. The result url was not found, but the problematic connection was unexpectedly seen:

We can see that no data is returned for the connection sent to 114.112.81.104. on the server, we can see that the local server of Site A only sends data to this address, but no response is returned:

It is concluded that port 80 of 114.112.81.104 can be called during login on Site A (the corresponding url can be found from the internal record ). Later, it was found that the url has expired and cannot be accessed. Therefore, when you log on, the invalid url will be called and the next step will be continued after the timeout. This is the real reason for the slow logon speed.