Integration and Messaging

Question 1

What are the 2 patterns of application communication?

Answer 1

• Synchronous (app to app)

- Asynchronous (app to queue to app)

Question 2

What is the default retention period for SQS messages?

Answer 2

4 days, maximum 14 days

Question 3

What size are SQS messages?

Answer 3

256KB

Question 4

What is a Delay Queue?

Answer 4

A queue that allows you to delay messages becoming available for consumers

Question 5

How long can you delay a message in the delay queue?

Answer 5

Up to 15 minutes

Question 6

What is the default time for delay queues?

Answer 6

0 seconds (immediately available)

Question 7

What parameter do you use to override the default delay for the delay queue?

Answer 7

DelaySeconds parameter

Question 8

What data type is a message body?

Answer 8

String

Question 9

What other options can be sent with a message body?

Answer 9

• Message attributes (metadata)

- Delay Delivery setting

Question 10

How many messages can a consumer receive at one time?

Answer 10

10

Question 11

What is visibility timeout?

Answer 11

The amount of time a message is invisible to other consumers after being picked up.

Question 12

What is the maximum visibility timeout?

Answer 12

12 hours

Question 13

What is the default visibility timeout?

Answer 13

30 seconds

Question 14

How do you change the visibility timeout?

Answer 14

Use the ChangeMessageVisibility setting in the API

Question 15

What is a Dead Letter Queue?

Answer 15

A queue that holds messages that have exceeded the redrive policy.

Question 16

What is a redrive policy?

Answer 16

The threshold of how many times a message can go back into the queue.

Question 17

What is Long Polling?

Answer 17

It allows a consumer to wait for a specified time for messages to become available.

Question 18

What is the wait time limit for Long Polling?

Answer 18

1 to 20 seconds

Question 19

What are the advantages of Long Polling?

Answer 19

• Decreases number of API calls

- Increases efficiency and latency of the application

Question 20

How do you set the Long Poll time via API?

Answer 20

Use the WaitTimeSeconds parameter

Question 21

What are the 3 default message attributes you can send with the body?

Answer 21

• Name
• Type
• Value

Question 22

How many messages per second can a FIFO queue handle?

Answer 22

300

Question 23

How do you send SQS messages larger than 256KB?

Answer 23

Use the SQS Extended Client

Question 24

How does the Extended CLient work?

Answer 24

It sends a small message to SQS and a large message to S3. The consumer then gets the large file from S3

Question 25

How do you publish SNS messages for mobile apps?

Answer 25

Use Direct Publish

Question 26

What are the 3 steps to use Direct Publish?

Answer 26

- Create a Platform Application - Create a Platform Endpoint - Publish to the Platform Endpoint

Question 27

What is the Fan-Out pattern?

Answer 27

It is when we use SNS and SQS together to prevent any data loss by pushing once in SNS and receiving in many SNS queues.

Question 28

What is AWS Kinesis?

Answer 28

It is the AWS alternative to Apache Kafka, which streams real-time big data such as logs, clickstreams, IoT etc.

Question 29

Is Kinesis Data automatically replicated?

Answer 29

Yes, into 3 Availability Zones

Question 30

How long can data be in a shard in Kinesis?

Answer 30

Up to 7 days, default is 1 day

Question 31

How many shards can a stream have?

Answer 31

Multiple

Question 32

How many messages can a shard write per second?

Answer 32

1000 messages p/s or 1MB/s

Question 33

How many messages can a shard read per second?

Answer 33

2MB/s

Question 34

What is resharding?

Answer 34

When we add shards to the stream

Question 35

What is shard merging?

Answer 35

When we subtract shards from the stream

Question 36

How do you put data into Kinesis via API?

Answer 36

Use PutRecord with a PartitionKey.

Question 37

What is the PartitionKey?

Answer 37

Identifies the partition/shard the data will be sent to.

Question 38

How do you prevent overloading specific shards?

Answer 38

Choose a partition key that is highly distributed, such as user_id

Question 39

What would you use to load data into Redshift, S3, ElasticSearch or Splunk?

Answer 39

Kinesis Firehose