SQS

Question 1

Which AWS service provides a secure, durable, and highly available hosted queue that can integrate and decouple distributed software systems and components?

Answer 1

Amazon Simple Queue Service (SQS)

Question 2

What are the two types of queues supported by SQS?

Answer 2

Standard and FIFO

Question 3

What is the maximum size of an SQS message?

Answer 3

256 KB, but messages can include links to larger data

Question 3

If VisibilityTimeout is set both on an SQS queue and on an individual message, which setting takes priority?

Answer 3

The setting applied to the message

Question 4

Which SQS attribute can be configured (either on the queue or per message) to handle error correction and automatic reprocessing?

Answer 4

VisibilityTimeout (0 seconds to 12 hours)

This attribute specifies the time required for message processing by the client, if processing fails, the message becomes available for retry after the VisibilityTimeout period

Question 5

What action must a client explicitly perform after successfully processing an SQS message?

Answer 5

The client must delete the message from the queue

Question 6

Where are problematic SQS messages typically redirected for further analysis?

Answer 6

To a Dead-Letter Queue, which is configured to retain unsuccessfully processed messages for further investigation

Question 7

What is the common integration pattern between SQS and Auto Scaling Groups (ASG)?

Answer 7

ASG can scale based on the length of the SQS queue

Question 8

What integration does SQS support for serverless message processing?

Answer 8

SQS can invoke AWS Lambda functions when messages appear in the queue

Question 8

What is the common integration pattern between SQS and SNS?

Answer 8

Fanout architecture, where a message sent to an SNS topic is received by multiple SQS queues subscribed to that topic, triggering message processing

Question 9

What polling types are supported by SQS?

Answer 9

Short-polling and Long-polling

Question 10

Which polling type immediately consumes requests and returns 0-10 messages?

Answer 10

Short-polling

Question 11

In which polling type is if messages are available on the queue they will be received, and if not the request will wait for specified waitTimeSeconds (up to 20sec) for messages to arrive?

Answer 11

Long-polling, the more cost-effective approach

Question 11

Does SQS support server-side encryption?

Answer 11

Yes, SQS supports server-side encryption with AWS KMS for messages at rest and encryption in transit for messages transferred between SQS and clients

Question 12

How is access to the SQS queue managed within AWS?

Answer 12

Through identity-based policies (within the same account) or resource-based policies (SQS Queue Policy) for access from external accounts

Question 13

What is the billing model for the SQS service?

Answer 13

SQS is billed based on the number of requests, where one request can include 0-10 messages, and up to 64 KB of data

Question 14

Which SQS queue type is the best effort and may deliver messages out of order?

Answer 14

Standard

Question 15

Which SQS queue type guarantees at-least-once delivery?

Answer 15

Standard

Question 15

Which SQS queue type offers better scaling with near-unlimited Transactions Per Second (TPS)?

Answer 15

Standard

Question 16

Which SQS queue type is typically used for decoupling application components, worker pools, and batching for further processing?

Answer 16

Standard

Question 16

Which SQS queue type guarantees message order?

Answer 16

FIFO

Question 17

Which SQS queue type guarantees exactly-once delivery?

Answer 17

FIFO

Question 18

Which SQS queue type provides 3,000 messages per second with batching, and 300 messages per second without batching?

Answer 18

FIFO

Question 19

Which SQS queue type is used for workflow and command ordering?

Answer 19

FIFO

Question 20

What suffix must be included in the SQS queue name when creating a FIFO queue?

Answer 20

The .fifo suffix (e.g. orders.fifo)

Question 21

What trade-off is involved when choosing between SQS FIFO queues and SQS Standard queues?

Answer 21

Choosing FIFO queues sacrifices performance (compared to Standard queues) in favour of preserving message order

Question 22

What SQS attribute can be used to delay the delivery of new messages to consumers for several seconds?

Answer 22

DelaySeconds (0 seconds to 15 minutes) attribute delays message visibility in the queue for the specified period before the messages become visible

Question 23

If DelaySeconds is set both on the SQS queue and on an individual message, which setting takes priority?

Answer 23

The setting applied to the individual message

Question 24

Is DelaySeconds attribute supported on SQS FIFO queues?

Answer 24

No, DelaySeconds is not supported on FIFO queues

Question 25

Which AWS service is most suitable for implementing worker pools, decoupling, or asynchronous communication?

Answer 25

Amazon Simple Queue Service (SQS)

Question 25

What configurations should be set for an SQS queue to redirect failed messages to a Dead-Letter Queue (DLQ)?

Answer 25

Configure a re-drive policy

DLQ should generally have a longer retention period than the original queue, and an alarm can be set up to notify about messages delivered to the DLQ

Question 26

Which AWS service is the best choice when there is one producer group and one consumer group, with no need for persistence (messages are deleted after processing)?

Answer 26

Amazon Simple Queue Service (SQS)