Root cause: ensure_structured_column() executed a synchronous blocking
engine.connect().execute(SELECT information_schema.columns ...) inside the
async request path (_build_chat_history / _maybe_compress_history), freezing
the uvicorn event loop and hanging all endpoints (~200s, recovered only by
docker restart).
Fix:
- chat_context.py: remove per-request ensure_structured_column() calls; run
once idempotently at app startup (main.py lifespan). Use CURRENT_DATABASE()
for PostgreSQL compatibility.
- main.py: add startup-only ensure_structured_column() hook (try/except).
- llm_client.py: trust_env=False + bounded httpx.Timeout/wait_for so broken
endpoints fail fast instead of hanging the event loop.
- chat_service.py: run media generation in a background daemon thread with its
own event loop (_launch_media_task_bg) so SSE end does not cancel image/video
tasks (#811); remove TEMP faulthandler diagnostic.
Safe-align: persist accumulated live container changes (admin/*, knowledge,
market, models, config, observability, mcp_client, platform_knowledge,
im_bot_platform, chat_media, capability_registry, requirements) and add
workflow_templates.
Verified: live failover test (model-006 -> conn-refused) returns in ~1.9s with
concurrent login 0.83s/200; event-loop responsiveness restored (sub-second).
QihuAI Design