SQS triggered lambda function not creating more than 1 instance.

Question

I have created a SQS FIFO queue and added a lambda function as a trigger. The problem I am running into is that whenever i put in messages (tested it with 60 messages) in the queue only 1 lambda instance is created. Even though there are 50 more messages (Batch size is 10) still in the queue.

I have waited for about 10 minutes the time it takes to process all the messages in the queue still only 1 instance is doing the job for that whole duration and any other instance is not getting created. I can tell because I can only see 10 messages in flight for the whole duration.

Details about the lambda function and SQS:
* Lambda timeout: 15 minutes
* Lambda memory: 2048mb
* Batch size: 10
* Maximum concurrency: 200
* Default visibility timeout: 15 Minutes
* Delivery delay: 0 Seconds
* Receive message wait time: 20 Seconds

Accepted Answer

Hi

Does your messages in the queue have different message group ID?
Since it'c a FIFO queue messages with the same ID will be processed in order, as per documentation:
`Amazon SQS ensures that messages in the same group are delivered to Lambda in order. Lambda sorts the messages into groups and sends only one batch at a time for a group`
https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#events-sqs-scaling

SQS triggered lambda function not creating more than 1 instance.

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