Issues with Async SQLAlchemy Queries in FastAPI - Receiving Incorrect Results
I'm working on a project and hit a roadblock. I've encountered a strange issue with I've been banging my head against this for hours. I'm working on a personal project and I'm facing an issue when trying to execute asynchronous queries using SQLAlchemy in my FastAPI application. I have defined an asynchronous endpoint to fetch user data, but I'm consistently getting outdated results. For instance, when I create a new user and immediately try to fetch it, it still returns users from the previous state, not including the newly created user. Here’s what my FastAPI route looks like: ```python from fastapi import FastAPI, Depends from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine from sqlalchemy.orm import sessionmaker, selectinload from models import User DATABASE_URL = "postgresql+asyncpg://user:password@localhost/dbname" engine = create_async_engine(DATABASE_URL, echo=True) SessionLocal = sessionmaker(bind=engine, class_=AsyncSession, expire_on_commit=False) app = FastAPI() async def get_db(): async with SessionLocal() as session: yield session @app.post("/users/") async def create_user(user: User, db: AsyncSession = Depends(get_db)): db.add(user) await db.commit() await db.refresh(user) return user @app.get("/users/{user_id}") async def read_user(user_id: int, db: AsyncSession = Depends(get_db)): result = await db.execute(select(User).filter(User.id == user_id)) return result.scalars().first() ``` I’ve verified that the user creation process works correctly, as it returns the user data right after creation. However, when I call the `/users/{user_id}` endpoint immediately after creating a user, the response is inconsistent and often returns an older version of the data. I initially thought this might be related to session scope, so I tried different configurations with the session lifecycle, but the issue persists. I have also made sure that the object is refreshed after committing changes, yet the results remain stale. Here are the versions I'm using: - FastAPI: 0.68.0 - SQLAlchemy: 1.4.22 - asyncpg: 0.24.0 Any ideas on what’s going wrong? Is there something specific to the async context that I might be missing? I'm working on a web app that needs to handle this. What's the best practice here? I'm working on a web app that needs to handle this. Any ideas what could be causing this? Any examples would be super helpful.