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Max Memory Used Incorrect

See original GitHub issue

Description:

When using the python 3.8 lambda runtime the ‘Max Memory Used’ always shows the same number as the total memory allocated.

Steps to reproduce:

Running any python 3.8 lambda w/ v 1.13.2

Observed result:

Max Memory Used always = Memory Allocated

Expected result:

Expected result is the actual memory usage of the Lambda

Additional environment details (Ex: Windows, Mac, Amazon Linux etc)

OS: Linux Centos 7
sam --version: 1.13.2

Other versions: awscli: 1.18.189 botocore: 1.19.14 boto3: 1.13.19

Issue Analytics

State:
Created 3 years ago
Reactions:4
Comments:9 (2 by maintainers)

Top GitHub Comments

1reaction

tazsinghcommented, Jan 5, 2021

@jfuss For the original issue, would it be possible to omit that false “Max Memory Used” entirely if it’s not possible to make it accurate? At least then it wouldn’t be misleading

For my comment, ah ok, I was unaware that AWS Lambda itself didn’t provide an OOM error. Thanks for the tip about the various behaviours 👍 Some sort of improvement would certainly be appreciated and I’ll inform you if something does come to mind

1reaction

tazsinghcommented, Jan 2, 2021

the issue is “fixed” by downgrading to 1.12.0

And unfortunately losing all the features in subsequent releases 😅 I’m really enjoying the official Warm Containers feature from 1.14!

I was bit by this quite badly recently, not strictly because the Memory Usage is the same as the Memory Size, but because there is no error telling me there is an Out Of Memory error when it actually happened. The Lambda just fails once the memory limit is hit, with the following output:

END RequestId: 45832c6d-7be9-49f6-a7d0-f4540affad04
REPORT RequestId: 45832c6d-7be9-49f6-a7d0-f4540affad04        Duration: 1731.93 ms    Billed Duration: 1800 ms      Memory Size: 256 MB  Max Memory Used: 256 MB
Invalid lambda response received: Lambda response must be valid json
2021-01-02 13:17:40 127.0.0.1 - - [02/Jan/2021 13:17:40] "GET / HTTP/1.1" 502 -

Note: I’m not even getting the opportunity to respond, the process just quits as soon as the memory limit is reached. So that ‘invalid JSON response’ message had me chasing the wrong goose.

Given the limitation to display the memory usage, would it be possible to notify me that an OOM error has occurred such that I can debug accordingly?

Thanks!