Integration and Messaging Flashcards
What are the 2 patterns of application communication?
- Synchronous (app to app)
- Asynchronous (app to queue to app)
What is the default retention period for SQS messages?
4 days, maximum 14 days
What size are SQS messages?
256KB
What is a Delay Queue?
A queue that allows you to delay messages becoming available for consumers
How long can you delay a message in the delay queue?
Up to 15 minutes
What is the default time for delay queues?
0 seconds (immediately available)
What parameter do you use to override the default delay for the delay queue?
DelaySeconds parameter
What data type is a message body?
String
What other options can be sent with a message body?
- Message attributes (metadata)
- Delay Delivery setting
How many messages can a consumer receive at one time?
10
What is visibility timeout?
The amount of time a message is invisible to other consumers after being picked up.
What is the maximum visibility timeout?
12 hours
What is the default visibility timeout?
30 seconds
How do you change the visibility timeout?
Use the ChangeMessageVisibility setting in the API
What is a Dead Letter Queue?
A queue that holds messages that have exceeded the redrive policy.