AWS DynamoDB query too slow (using query, not Scan)

Question

It's my first time with AWS Lambdas and DynamoDB, in Python.

I have my Table with only 474 records and a total weight of 890,4 kilobytes. The filtered selection is around only 380 records.

Quite small, but still it takes severall seconds to query. Really too slow.

I use a global secondary index, as it's supposed to be the way to filter the collection.

dynamo = boto3.resource('dynamodb', region_name='us-east-1',
     aws_access_key_id='my_key',
     aws_secret_access_key= 'my_key')

table = dynamodb.Table('my_table_name')

response = table.query(
    IndexName='venta_arge_ok-index',
    KeyConditionExpression=Key('venta_arge_ok').eq('True'))

When I test the Lambda in the console I get this figures:

Memory Size: 128 MB
Max Memory Used: 84

Run the test several times and got consistent times around 3 sec:

Duration: 3270.27 ms
Duration: 3069.37 ms
Duration: 3290.68 ms
Duration: 3013.34 ms
Duration: 3157.71 ms

What am I missing here? Thanks!

Did you try increasing the Lambda function timeout to see if it eventually succeeds? It could be timing out due to a network misconfiguration, if you deployed the Lambda function in a VPC. — Mark B
– Mark B, Commented Apr 7, 2022 at 20:10
@MarkB just updated the info, after increasing the timeouot. The query is just above 3 sec, but it seems still too much for such a small data collection. Or maybe it's normal and I'm confused? — Francisco Ghelfi
– Francisco Ghelfi, Commented Apr 7, 2022 at 21:29
Is Lambda function in the same AWS region as the DynamoDB table? us-east-1? — Mark B
– Mark B, Commented Apr 7, 2022 at 22:08
Typically no need for access key and secret key in a Lambda function. Assign the appropriate permissions to the IAM role you configure the Lambda function with. — jarmod
– jarmod, Commented Apr 7, 2022 at 22:37
Try increasing the function size as well. 128MB is so small. Take note that increasing memory size also increases CPU and network. — Noel Llevares
– Noel Llevares, Commented Apr 8, 2022 at 1:28

Francisco Ghelfi · Accepted Answer · 2022-04-08 03:24:10Z

5

As Noel Llevares pointed, the issue was related with memory size (and it's related CPU power increase).

The same Lambda gave the following results for each memmory size tested:

128 MB - 3 sec 256 MB - 1.5 sec 512 MB - 0.75 sec 1024 MB - 0.4 sec

answered Apr 8, 2022 at 3:24

Francisco Ghelfi

9621 gold badge16 silver badges39 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

AWS DynamoDB query too slow (using query, not Scan)

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related