History session data with mysql db session service didn't display as expected time order

[Colstuwjx]

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Describe the bug
I've used pymysql and database session service to store the adk chat session data, however, it seems like the session chat data didn't show as expected.

related api: GET http://127.0.0.1:8080/apps/my_agent/users/user/sessions/1be66d52-36e3-4092-99cb-a795957d0680

api response data:

...
        {
            "content": {
                "parts": [
                    {
                        "text": "I need to transfer to the `knowledge_retrieve_agent` to retrieve the document.\n\n"
                    },
                    {
                        "functionCall": {
                            "id": "adk-8f521665-f854-4a76-b4cd-b03d8677ab0c",
                            "args": {
                                "agent_name": "knowledge_retrieve_agent"
                            },
                            "name": "transfer_to_agent"
                        }
                    }
                ],
                "role": "model"
            },
            "invocationId": "e-a647fe88-20dd-4ecc-b3a5-3fa982efc40d",
            "author": "problem_analysis_agent",
            "actions": {
                "stateDelta": {},
                "artifactDelta": {},
                "requestedAuthConfigs": {}
            },
            "longRunningToolIds": [],
            "id": "fzfUoYlX",
            "timestamp": 1748243390.0
        },
        {
            "content": {
                "parts": [
                    {
                        "text": "please use rag to retrieval the doc "
                    }
                ],
                "role": "user"
            },
            "invocationId": "e-a647fe88-20dd-4ecc-b3a5-3fa982efc40d",
            "author": "user",
            "actions": {
                "stateDelta": {},
                "artifactDelta": {},
                "requestedAuthConfigs": {}
            },
            "longRunningToolIds": [],
            "id": "zgrx7klz",
            "timestamp": 1748243390.0
        },
...

As we can see, the timestamp same to be 1748243390.0, I'm wondering if it's the root cause.

To Reproduce
Steps to reproduce the behavior:

1. Install google-adk==1.0.0 and pymysql, use mysql as session storage
2. Run 'uvicorn main:app --host 0.0.0.0 --port 8080' to start the adk web service
3. Open 'http://127.0.0.1:8080' and try to chat several rounds with the agent, close and re-open it
4. You may see the disorder issue as well

Expected behavior
chat history should be ordered by the original asking order.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: macOS
• Python version(python -V): 3.12.7
• ADK version(pip show google-adk): 1.0.0

Additional context

[Colstuwjx]

BTW, when I changed to use In Memory service to store the session, I've found the timestamp is more accurate, e.g. "timestamp": 1748252897.871782, and no disorder issue any more.

[wyf7107]

@DeanChensj Could you help check if this is session service storing issue? (I think UI should be rendering the correct order but the storing part has some bug)

[DeanChensj]

Hi @Colstuwjx , the issue is that mysql use single digit precision by default, you can workaround by setting

  timestamp: Mapped[DateTime] = mapped_column(DateTime(6), default=func.now())

The offical fix should be included in the next 1 or 2 release.

[Colstuwjx]

the issue is that mysql use single digit precision by default, you can workaround by setting

Sorry, may I know where to set this setting ?

[Colstuwjx]

I've tried to set the Datetime to Datetime(6) at this line , and deployed this forked version to test, however, it seems like the event time is still with .0 precision, any ideas ?

[Colstuwjx]

proposed PR #1001 for fixing this.