Decoupling Services Flashcards
What benefits does tightly coupled architecture have over loosely coupled architecture?
No meaningful benefits
What does SQS stand for?
Simple Queue Service?
What is SQS?
SQS is a messaging queue that allows asynchronous processing of work
What range of values can the delivery delay be set to?
0 seconds to 15 minutes
What is the maximum message size in SQS?
256 KB
What format must the message in SQS be?
text in any format
What type of encryption is default and what type of encryption must be specified for SQS?
Encryption in transit is default and encryption at rest can be added
What is the default message retention?
4 days
What type of polling is default for SQS?
short
What is the difference between long pulling and short pulling? Which is typically better?
Long pulling waits for a response while short polling disconnects and reconnects to check for responses. Long pulling is typically better
What is queue depth?
A trigger you can configure to autoscale
What is default length for visibility time out?
30 seconds
What is the purpose of a visibility timeout?
Holds a message to ensure the message is retained if the receiver fails to process a message
How long can messages last in SQS?
up to 14 days
what is a dead letter queue?
another SQS queue that you can sideline messages that aren’t working to
What is the max retention window in DLQ?
Same as SQS, 14 days
What is the standard SQS message ordering?
Best Effort ordering
Which SQS message ordering type prevents duplications?
FIFO
Which SQS ordering type has better performance
Standard
Which SQS ordering type costs more?
FIFO
What does SNS stand for?
Simple notification service
What does SNS do?
It is a push-based messaging service that proactively delivers messages to the endpoints subscribed to it
What is the maximum message size for SNS?
256KB
Can SNS messages that fail to be delivered be stored in an SQS DLQ?
Yes
