A while ago, I was asked by shareholders about the news push platform Austin Interface performance related issues , I thought I could arrange a wave of articles early . I really didn't expect that there were so many online problems in my work these two weeks , Stayed up for a few days and nights , Cause the article to drag to the present .

The message push platform will provide the interface for the business party to call , Generally, the interviewer will also want to ask ：「 How many interfaces do you have QPS？RT How much is the ？ Have you measured the pressure ？ Business growth , The number of calling interfaces is also growing , What would you do at this time ？」

For this question , Let me provide some ideas , You can do some simple trimming according to your own technology stack .

Talk about some indicators and system business / framework

our QPS and RT All indicators come from logs , We print out the time-consuming when the interface is called （RT） And recorded a log （QPS）. With this log , We go through GrayLog You can configure QPS and RT We're monitoring it . therefore , Our interface is right QPS and RT They are all monitored

Deployed in the access layer 4 platform 4C8G Machine , Through monitoring, we can see , Everyday QPS About 100 grades （200 about ）, The peak value recorded during the great acceleration is 2000,RT In about 20ms.

The sending interface provides single sending and batch interfaces . If there is a need to push messages in batches , We suggest that businesses adopt batch interface , In this way, the network can be reduced to a certain extent IO, What I undertake QPS Not too big .

But then again , The pressure at the interface level is not great . Back to our system architecture , We have access layer ->MQ-> Send logical layer , What the access layer does is just assemble parameters , Then send the message to MQ 了 .

As for pressure measurement , I haven't operated here , It's usually for testing , I'm not sure about this . But after the system takes shape , Sending messages is really not easy , Pressing the access layer doesn't make much sense （ as long as MQ Can withstand , Then the access layer is not a problem ）.

The rate bottleneck of sending messages is generally on the downstream channel side , We call SMS / Mail and other channels will limit the speed , Different channels are different . There are probably several indicators ：

• Tencent cloud SMS 3000QPS（ However, we will load several SMS channels ）

• Tencent enterprise email probably only supports below 100 QPS（ It was raised , It will limit the sending failure , No specific QPS）

• A push PUSH We send by number （8000 people /QPS） Limit

• and IM It's our own research （ All notification classes need to enter MySQL And risk control ）, Limit the number of people to 600 people /QPS

• ...

In the consumer MQ When , Each type of message channel will have a corresponding thread pool for consumption , And this is a dynamic thread pool （ You can adjust the parameters of the thread pool without restarting publishing ）

As the business grows , When QPS It's really coming up （ More connections ）, We just need to expand the capacity horizontally , For the access layer, it is stateless .

summary

When we are in charge of a system , It is necessary to provide an interface for the business party to call , We need to know the indicators of this interface and the corresponding upstream and downstream . So when there is a problem , You can find problems according to historical indicators , Go to the upstream and downstream to remind you of the risks .

The interviewer asked about the performance of the interface /QPS Or the pressure test is mainly to see whether you really understand what you are responsible for , If search / recommend / The flow interface is also relatively good for pressure measurement , But send a message / Order / It's not easy to pay for interfaces like this .

We can express the indicators of the interface and the details of related businesses , Then the general interviewer will not correct you （ Unless this interviewer also happens to do this business ）

Also want to know Austin What interview questions does the message push platform ask ？ Let me know in the comment area ！