Queues in message brokers in Data Structures Theory - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the role of queues in message brokers

What is the primary purpose of a queue in a message broker system?

A To store messages temporarily until they are processed by consumers

B To permanently save messages for future reference

C To prioritize messages based on their size

D To encrypt messages before sending them

💡 Hint

Think about how messages are handled between producers and consumers.

Queues in message brokers act as temporary storage holding messages until consumers are ready to process them. This ensures reliable communication between different parts of a system.

📋 Factual

intermediate

Message ordering in queues

Which statement best describes message ordering in a typical queue of a message broker?

A Messages are processed in reverse order of arrival (LIFO)

B Messages are processed randomly without any order

C Messages are processed based on their priority by default

D Messages are always processed in the order they arrive (FIFO)

💡 Hint

Consider the common queue behavior acronym FIFO.

Queues typically follow First-In-First-Out (FIFO) order, meaning messages are processed in the same order they arrive.

🔍 Analysis

advanced

Impact of queue size limits on message brokers

What happens when a message broker's queue reaches its maximum size limit?

A New messages are rejected or blocked until space is available

B Oldest messages are automatically deleted to make space

C Messages are compressed to fit more in the queue

D The queue size automatically increases without limit

💡 Hint

Think about how systems prevent overload and maintain stability.

When a queue is full, the broker typically rejects or blocks new messages to avoid losing data or crashing.

❓ Comparison

advanced

Difference between durable and non-durable queues

Which of the following correctly contrasts durable and non-durable queues in message brokers?

A Non-durable queues save messages permanently; durable queues delete messages after processing

B Durable queues process messages faster than non-durable queues

C Durable queues save messages to disk to survive broker restarts; non-durable queues do not

D Non-durable queues encrypt messages; durable queues do not

💡 Hint

Consider what happens to messages if the broker restarts unexpectedly.

Durable queues store messages on disk so they survive restarts, while non-durable queues keep messages only in memory and lose them if the broker stops.

❓ Reasoning

expert

Effect of multiple consumers on a single queue

In a message broker, what is the typical effect of having multiple consumers reading from the same queue?

A Only the first consumer receives messages; others wait

B Messages are distributed among consumers, allowing parallel processing

C All consumers receive every message, duplicating processing

D Messages are processed in reverse order to balance load

💡 Hint

Think about how queues help scale processing by sharing work.

Multiple consumers on one queue share the messages so each message is processed by only one consumer, enabling parallelism and faster throughput.