Bedrock Agent Streaming API delays response and serializes parallel requests

Question

We are encountering a critical performance issue with the AWS Bedrock Agent API when using the streaming feature — tested using both Python (AWS Lambda) and Java (Spring Boot service).

Observed issues:

Stream requests are serialized: When multiple streaming requests are made in parallel, only one request is processed at a time. The next request only starts after the previous one completes. This happens both in Python Lambda (using async parallel invocations) and in Java running a multithreaded web service.

Streaming starts only after full response is ready: Although the streaming API is expected to return partial chunks quickly (as it does via the Bedrock console), we observe that the first stream chunk is only sent after the entire response is seemingly generated.

For example:

Invocation started at: 04:21:28.265
First stream chunk received at: 04:21:36.972

![Saisissez la description de l'image ici](/media/postImages/original/IMkiL9htt9TfahilEY21YcCA)

This delay is identical to what we’d see from a full non-streamed response, suggesting that the Agent buffers the entire response before emitting any streamed content.

This behavior completely defeats the purpose of using streaming, and blocks us from deploying Bedrock Agents in production for our use case.

Question:

Is this a known limitation or issue with Bedrock Agent streaming?

Is there any recommended configuration or workaround to achieve true parallelism and low-latency streaming similar to what the Bedrock Console provides?

We’re currently considering alternatives if we cannot resolve this, so any help would be appreciated.

re:Post Agent · Answer

The issues you're experiencing with AWS Bedrock Agent streaming API are indeed known limitations that have been reported by other users as well. Let's address each of your observed issues:

1. Serialization of stream requests:
The behavior you're seeing where multiple streaming requests are processed one at a time, rather than in parallel, is likely related to service quotas and rate limiting implemented by Amazon Bedrock. This is a common practice to maintain service performance and ensure fair usage across all users. The service may be enforcing a limit on the number of simultaneous requests that can be processed for your account.

2. Delayed start of streaming:
The delay you're observing before receiving the first stream chunk is a known issue with the current implementation of Bedrock Agent streaming. As you've correctly noted, it appears that the agent is buffering the entire response before beginning to stream, which negates much of the benefit of using a streaming API.

To address these issues, consider the following options:

1. Check and request quota increases:
Review your current Amazon Bedrock quotas in the AWS Management Console or using the AWS CLI. If you find that your current quota is limiting your concurrent API requests, you can open a support case with AWS to request an increase. Explain your use case and the need for higher concurrency.

2. Implement request rate limiting:
On your application side, you could implement a queue or rate limiting mechanism to manage the flow of requests to the Bedrock API. This can help prevent exceeding quotas and ensure smoother operation.

3. Optimize your agent:
Try to optimize your agent to process requests more quickly, which could reduce the likelihood of requests being queued and potentially improve overall response time.

4. Consider alternative APIs:
While not specific to Bedrock Agents, Amazon Bedrock does offer other streaming capabilities that might be relevant to your use case. For example, the InvokeModelWithResponseStream API operation allows you to invoke a specified Amazon Bedrock model and receive the response in a stream. Similarly, the ConverseStream API provides a consistent interface for interacting with different models that support streaming.

5. UI enhancements:
To improve user experience while waiting for responses, consider adding visual cues in your application (like loading indicators) to show that the agent is processing the request.

It's worth noting that even with streaming support, the benefits for Bedrock Agents might be limited since agent responses often involve multiple chained LLM calls, with only the final generation being potentially streamable.

Given the current limitations, if low-latency streaming and true parallelism are critical for your use case, you may need to explore alternative solutions or wait for potential future updates to the Bedrock Agent API. Keep an eye on AWS announcements and documentation for any updates, as AWS regularly enhances its services.

For the most up-to-date information and specific guidance on your use case, it would be advisable to contact AWS Support directly.  
**Sources**  
[Requests to Invoke Agent in Bedrock are being queued | AWS re:Post](https://repost.aws/questions/QUZMEI2sJwR4CHmT12ZeoYbA/requests-to-invoke-agent-in-bedrock-are-being-queued)  
[Issue streaming response from bedrock agent | AWS re:Post](https://repost.aws/questions/QU_jIzfKIAQHSXyPeE4JMAJg/issue-streaming-response-from-bedrock-agent)  
[AWS Bedrock Agents Support Streaming Responses? | AWS re:Post](https://repost.aws/questions/QUsqK6QQwoQ-a-crTHpkjfEA/aws-bedrock-agents-support-streaming-responses)

Bedrock Agent Streaming API delays response and serializes parallel requests

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