Background execution error: 'NoneType' object has no attribute 'update_timestamp_tz'

[ananthanarayanan431]

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Describe the bug
DatabaseSessionService is not working for postgresql and i;m using working combination of Google-adk and AG UI

To Reproduce
Please share a minimal code and data to reproduce your problem.
Steps to reproduce the behavior:

1. Install
   python version - 3.12.9
   google-adk - 1.18.0
2. Run via ag-ui protocol
3. Open '....'
4. Provide error or stacktrace

Expected behavior
I'm using the postgresql here for DatabaseSessionService and it can't able to persist the information in events tables in postgres
agent= ADKAgent( adk_agent=agent, user_id_extractor=extract_user_id, app_name_extractor=extract_app_name, session_timeout_seconds=3600, session_service=DatabaseSessionService(db_url=POSTGRES_DB_URL), use_in_memory_services=True, memory_service=shared_memory_service, )

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

Desktop (please complete the following information):

• OS: MAC
• Python version(python -V): 3.12.9
• ADK version(pip show google-adk): 1.18.0

Model Information:

• Are you using LiteLLM: Yes/No : no
• Which model is being used(e.g. gemini-2.5-pro): gemini-2.5-flash

Additional context
Add any other context about the problem here.

[ananthanarayanan431]

@DeanChensj can you give some updates please. We're facing this issue

[ananthanarayanan431]

@DeanChensj any updates? and please let me know what is causing this issue

[wuliang229]

We need more information on how to reproduce. @ananthanarayanan431 is this a new DB? How did you interact with the DB and what were the sequence of events? One possibility is that you are appending an event to a non-existent session, and therefore seeing the NoneType error. Could you check if the session information you passed to the append_event() method is correct, i.e. the session was created before?