AWS SQS — In a NutShell

2 min readApr 17, 2023

Overview

SQS is a queue, e.g a Kinesis data streams producer can send messages to the SQS queue.
Consumer will poll messages from the queue.
Fully Managed.
Very low latency, less than 10ms!
No limit to how many messages can be in the queue.
Default retention is 4 days, but this can be increased up-to 14 days.
Can have duplicates messages (at least once delivery).
Offers best effort ordering, but no guarantees.
Messages have a limit of 256KB per message sent.
Messages are defined in the body and are of type string.
Can optionally provide a delay on delivery.
Response back once a message has been sent to SQS queue. This will contain a message identifier and a MD5 hash of the body.

Poll for messages, can do up-to 10 messages at a time.
Consumer will delete the message once it has been consumed via the message ID & receipt handle. Therefore, messages cannot be processed by multiple applications.

Names of the queue must end in .fifo
Can send up-to 3,000 message/s compared to a standard queue with batching enabled and 300 without.
Messages are processed in the exact order from the consumer that pushed them.
Messages are sent exactly once.
Can send large messages with SQS extended client (Java library). Producer will send the large payload 10GB to an s3 bucket and a small metadata message to the SQS queue, the consumer will then pull the metadata containing the bucket id to access the much larger payload.