Lambda concurrency and throttling in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is concurrency in AWS Lambda?

Concurrency in AWS Lambda means how many function instances can run at the same time to handle incoming requests.

beginner

What happens when Lambda concurrency limit is reached?

When the concurrency limit is reached, new requests are throttled, meaning they are delayed or rejected until capacity frees up.

intermediate

What is reserved concurrency in AWS Lambda?

Reserved concurrency is a set number of concurrent executions that are guaranteed for a specific Lambda function, protecting it from being throttled by other functions.

intermediate

How does AWS Lambda handle throttled requests?

Throttled requests are either retried automatically by AWS services or return an error to the caller, depending on the integration and retry settings.

beginner

Why is it important to manage Lambda concurrency?

Managing concurrency helps avoid throttling, ensures fair resource use, and keeps your application responsive under load.

What does Lambda concurrency limit control?

A Number of function instances running at the same time

B Maximum size of the function code

C Duration a function can run

D Amount of memory allocated

Concurrency limit controls how many Lambda function instances can run simultaneously.

What is the effect of throttling in Lambda?

A Function logs are deleted

B Function runs faster

C Function memory increases

D Requests are delayed or rejected

Throttling means new requests are delayed or rejected when concurrency limits are reached.

What does reserved concurrency guarantee?

A Function has dedicated concurrency capacity

B Function logs are stored longer

C Function runs only once

D Function timeout is extended

Reserved concurrency guarantees a set number of concurrent executions for a function.

If a Lambda function is throttled, what might happen?

A It automatically scales memory

B It increases timeout

C It retries or returns an error

D It deletes old versions

Throttled requests may be retried or return errors depending on settings.

Why should you monitor Lambda concurrency?

A To reduce function code size

B To avoid throttling and keep performance steady

C To increase function timeout

D To delete unused functions

Monitoring concurrency helps avoid throttling and keeps your app responsive.

Explain what Lambda concurrency is and why it matters for your application.

Think about how many functions run at once and what happens if too many run.

Describe what throttling means in AWS Lambda and how reserved concurrency can help.

Consider what happens when Lambda hits its limits and how to protect important functions.