dify The /v1/chat-messages interface is very slow

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Dify version

0.8.2

Cloud or Self Hosted

Self Hosted (Docker)

Steps to reproduce

Given that the issue of slow response times with the /v1/chat-messages API endpoint began after upgrading to version 0.8.2, it's likely that the upgrade introduced changes affecting performance

When using the console page for debugging, the speed is very fast.

It seems that when you use the /v1/chat-messages API endpoint, the response is slow, and this slowness is also reflected in the console logs. This indicates that the issue is likely not related to network.

✔️ Expected Behavior

No response

❌ Actual Behavior

No response

Sep 25 '24 03:09 rechardwang

Hey @rechardwang! 👋 I'm here to help you with any bugs, questions, or contributions you have for the project. Let's work together to solve this issue!

I found some similar issues and discussions that might help you troubleshoot the slow response times with the /v1/chat-messages API endpoint:

Discussion: When publishing Api, ''/chat-messages'' api responds slowly with data in streaming mode (Unsolved) ^[1].
Issue: chat-messages API is taking more time compared to test run in dify (Closed) ^[2].
- Suggested Solution: Implement streaming output in the invoke_llm method to improve responsiveness. Here is the suggested code modification:
```
llm_result: LLMResult = model_instance.invoke_llm(
    prompt_messages=prompt_messages,
    model_parameters=app_orchestration_config.model_config.parameters,
    tools=[],
    stop=app_orchestration_config.model_config.stop,
    stream=True,  # Enable streaming
    user=self.user_id,
    callbacks=[],
)
```
- Additionally, consider increasing the timeout value in the frontend code and implementing a reconnect feature to handle disconnections.
Issue: Self Hosted (Docker), api call /chat-messages with response_mode: streaming, the message_end response lasts up to 5 seconds (Closed) ^[3].
- Suggested Solution: The delay could be due to server processing time, network latency, server load, the overhead of streaming, or server-side configuration settings. It's recommended to check the server-side implementation, server logs, and possibly adjust server or network configurations.

For optimizing the performance of the /v1/chat-messages API endpoint, consider the following server and network configurations for running Dify in a self-hosted Docker environment:

API Server Configuration:
- DIFY_BIND_ADDRESS: Default is 0.0.0.0.
- DIFY_PORT: Default is 5001.
- SERVER_WORKER_AMOUNT: Number of API server workers, calculated as number of CPU cores x 2 + 1.
- SERVER_WORKER_CLASS: Default is gevent.
- GUNICORN_TIMEOUT: Default is 200. Recommended value is 360 to support longer SSE (Server-Sent Events) connection times.
Database Configuration:
- DB_USERNAME, DB_PASSWORD, DB_HOST, DB_PORT (Default: 5432), DB_DATABASE.
- SQLALCHEMY_POOL_SIZE: Default is 30 connections.
- SQLALCHEMY_POOL_RECYCLE: Default is 3600 seconds.
Redis Configuration:
- REDIS_HOST, REDIS_PORT (Default: 6379), REDIS_DB (Default: 0), REDIS_PASSWORD.
- REDIS_USE_SSL: Default is false.
Celery Configuration:
- CELERY_WORKER_CLASS: Default is gevent.
- CELERY_WORKER_AMOUNT: Default is 1.
- CELERY_BROKER_URL: Redis URL for Celery broker.
File Storage Configuration:
- STORAGE_TYPE: Default is local.
- STORAGE_LOCAL_PATH: Path for local storage.
Network Configuration:
- Ensure Docker containers can communicate with each other and with the database and Redis instances.
- Configure appropriate firewall rules to allow traffic on necessary ports (e.g., 5001 for API, 5432 for PostgreSQL, 6379 for Redis).

Example Docker Compose configuration snippet:

version: '3.8'
services:
  api:
    image: dify/api:latest
    environment:
      - DIFY_BIND_ADDRESS=0.0.0.0
      - DIFY_PORT=5001
      - SERVER_WORKER_AMOUNT=5  # Adjust based on CPU cores
      - GUNICORN_TIMEOUT=360
      - DB_HOST=your_db_host
      - DB_PORT=5432
      - REDIS_HOST=your_redis_host
      - REDIS_PORT=6379
      - REDIS_PASSWORD=your_redis_password
      - STORAGE_TYPE=local
    ports:
      - "5001:5001"
    volumes:
      - ./storage:/app/api/storage
  db:
    image: postgres:latest
    environment:
      - POSTGRES_USER=your_db_user
      - POSTGRES_PASSWORD=your_db_password
      - POSTGRES_DB=your_db_name
    ports:
      - "5432:5432"
  redis:
    image: redis:latest
    environment:
      - REDIS_PASSWORD=your_redis_password
    ports:
      - "6379:6379"

This configuration ensures that the Dify API server, PostgreSQL database, and Redis instance are properly set up and can communicate with each other, providing a robust environment for optimal performance ^[4]^[5]^[6].

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