High cpu usage in DynamoDbEnhancedAsyncClient

[cukyz]

I am using DynamoDbEnhancedAsyncClient.
When I did the performance test, the CPU usage was too high.
so I changed the awssdk version and it made a difference in CPU usage.

The version is as follows :

• awssdk 2.20.47 (before)
• awssdk 2.20.121 (after)
• java : amazon correcto 17

Code :

    @Autowired
    public TestRepository(DynamoDBProperty dynamoDBProperty, DynamoDbEnhancedAsyncClient dynamoDbEnhancedAsyncClient) {
        this.dynamoDbEnhancedAsyncClient = dynamoDbEnhancedAsyncClient;
        this.testDynamoDbAsyncTable = this.dynamoDbEnhancedAsyncClient.table(
                TABLE_NAME,
                TableSchema.fromImmutableClass(Test.class)
        );
    }

    @Override
    public Mono<Test> getItemByPartitionKey(String id) {

        String sk = "test#" + id.substring(10, 17);
        Key testKey = Key.builder().partitionValue(id).sortValue(sk).build();
        return Mono.fromCompletionStage(testDynamoDbAsyncTable.getItem(testKey));
    }
	
    @Override
    public Flux<Test> queryByPartitionKey(String id) {
        Key testKey = Key.builder().partitionValue(id).build();
        QueryConditional queryConditional = QueryConditional.keyEqualTo(testKey);
        QueryEnhancedRequest queryEnhancedRequest = QueryEnhancedRequest.builder()
                .queryConditional(queryConditional)
                .build();
        return Flux.defer(() -> Flux.from(testDynamoDbAsyncTable.query(queryEnhancedRequest)
                .flatMapIterable(Page::items)));
    }	

Both API - getItem and query have high CPU usage.
After changing the sdk version, the CPU usage decreased, but it still shows high CPU usage.
Here are the results.

When testing local PC
Vusers : 32

	ver 2.20.47	ver 2.20.121
TPS	737.8	809.4
CPU	20%	11%

Local - 737.8, CPU 20%

Local - 809.4, CPU 11%

When testing server
The server is configured in aws EC2.
I used ngrinder to load the server. (similar to jmeter)

Vusers : 100

	ver 2.20.47	ver 2.20.121
TPS	6,252.5	6,512.6
CPU	69.5%	62.4%

Why is the CPU usage so different depending on the sdk version?
So I have plan to update production to 2.20.121.

And if I test with ElastiCache instead of DynamoDB, the CPU usage is much lower.
Does the DynamoDB sdk know about this and do you have any plans to further reduce CPU usage?

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.