Hello, in this article, I will work with you to sort out the high-frequency test points of message queues in interviews, so as to review the past and learn the new.
How to examine message queues during interviews
Message queue is one of the most frequently used basic components in daily development, and related questions are naturally frequent in interviews.
There are two main ways to examine the message queue during the interview. One is for the related theories of the message queue, such as repeated consumption of the message queue, consumption idempotence, reliable transmission of the message queue, etc.; the other examination method is For a specific message queue middleware, examine the principles of component application, implementation solutions and application details, such as common message queue components such as Kafka, RabbitMQ, and RocketMQ.
Below I have sorted out some high-frequency questions in interviews. You can compare these questions to check whether you have mastered the content of the question examination, and make targeted improvements based on your weak links.
High-frequency issues in message queue theory
To examine the theories and designs related to message queue applications, the interviewer can ask the following series of questions:
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How to ensure the high availability of message queue?
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How to ensure that messages are not consumed repeatedly?
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How to ensure that consumption is idempotent?
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How to ensure the reliable transmission of messages?
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What should I do if messages are lost during transmission?
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How to ensure the order of messages?
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How to solve the message queue delay problem?
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How to solve the message queue expiration problem?
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What to do when the message queue is full?
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There are millions of messages that have been backlogged for several hours. What should be done?
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If you were asked to write a message queue, how would you design the architecture?
It can be seen that questions in this area attach great importance to examining the candidate's experience in handling practical problems, but there is no fixed answer. I have emphasized many times in my column that it is better to teach people to fish than to teach them to fish, and the distributed methodology is the most important. If you were asked to design a message queue from scratch, how would you expand it? You can start from the basic theory of distribution, from the consistency of data storage, cluster expansion, combined with what I explained in the distributed message queue module, and at the same time integrate your own understanding of the system architecture, and finally form your own point of view.
High-frequency problems in message queue applications
When examining a specific message component during the interview, the candidate generally has application experience in that component. The focus is on examining the depth of the candidate's mastery of the basic components and solutions to problems when problems arise.
Taking Kafka as an example, the following questions can be asked:
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Describe the design architecture of Kafka?
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What are the differences between Kafka, ActiveMQ, RabbitMQ, and RocketMQ?
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Is it possible that there is a duplicate consumption problem on the Kafka consumer side?
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Why is Kafka partitioned?
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How does Kafka ensure data consistency?
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What are ISR, OSR and AR in Kafka?
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Under what circumstances does Kafka experience message loss?
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Does Kafka message use Pull mode or Push mode?
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How does Kafka interact with ZooKeeper?
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How does Kafka achieve high throughput?
If it is RocketMQ, many problems are similar. You can start from the following questions to investigate:
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What are the differences between RocketMQ and ActiveMQ?
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Why doesn't RocketMQ lose messages?
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What are the applications of RocketMQ's transaction messages?
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How does RocketMQ ensure system high availability?
Some of these questions can be found in the columns, but most of them require your accumulation and thinking in daily life. For example, for the high availability of message queues, you can deploy it on multiple machines to prevent single points of failure; master-slave structure replication, Prevent message loss through message redundancy; analyze message persistence, ACK of disk writing, etc.
That’s it for today. You are also welcome to leave a message to share your interview experience and discuss it with everyone.