Postgres insert many causes InvalidRequestError: Can't match sentinel values in result set to parameter sets

[shabani1]

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Example Code

import asyncio
import uuid
from datetime import datetime
from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker
from sqlmodel import Field, SQLModel, Column, DateTime, func
from sqlmodel.ext.asyncio.session import AsyncSession

engine = create_async_engine("postgresql+asyncpg://postgres:postgres@localhost:5432/test_db", echo=True)
AsyncSessionLocal = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


class Item(SQLModel, table=True):
    __tablename__ = 'items'
    name: str
    item_id: uuid.UUID = Field(
        default_factory=uuid.uuid4,
        primary_key=True,
        index=True,
        nullable=False,
    )
    created_at: datetime = Field(
        sa_column=Column(DateTime(timezone=True), nullable=False, server_default=func.now()),
    )
    updated_at: datetime = Field(
        sa_column=Column(DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()),
    )
    collection_id: str = Field(default='default')


async def create_tables():
    async with engine.begin() as conn:
        await conn.run_sync(SQLModel.metadata.create_all)

async def drop_tables():
    async with engine.begin() as conn:
        await conn.run_sync(SQLModel.metadata.drop_all)

async def insert_item():
    async with AsyncSessionLocal() as session:
        async with session.begin():
            item = Item(name='This is an item')
            session.add(item)
            await session.commit()

async def insert_two_items():
    async with AsyncSessionLocal() as session:
        async with session.begin():
            item1 = Item(name='This is item 1')
            item2 = Item(name='This is item 2')
            session.add(item1)
            session.add(item2)
            await session.commit()

async def async_main():
    await drop_tables()
    await create_tables()
    await insert_item()  # this works
    await insert_two_items()  # this fails
    await drop_tables()

if __name__ == "__main__":
    asyncio.run(async_main())

Description

I have a UUID field as my primary key, and am inserting items as seen in the code above. Whenever I add two items to my session and commit, it leads to the following error:

InvalidRequestError: Can't match sentinel values in result set to parameter sets; key '34bdaa33-90fe-4058-a278-3561fe04ad70' was not found. There may be a mismatch between the datatype passed to the DBAPI driver vs. that which it returns in a result row. Ensure the given Python value matches the expected result type *exactly*, taking care to not rely upon implicit conversions which may occur such as when using strings in place of UUID or integer values, etc.

• The columns created_at and updated_at seem to cause the error -- without these columns it works as expected.
• I've created a SQLAlchemy issue here, which reproduces the error without using SQLModel, but it turns out this is expected behavior.
• The GUID class could be updated as described here to include _sentinel_value_resolver, or can be swapped out for the Uuid type as recommended here and here.

Operating System

macOS

Operating System Details

sqlalchemy==2.0.28

SQLModel Version

0.0.16

Python Version

3.11

Additional Context

No response

[YuriiMotov]

Works fine in current version (0.0.24):

Output in the details:

2025-08-20 23:18:18,837 INFO sqlalchemy.engine.Engine select pg_catalog.version()
2025-08-20 23:18:18,837 INFO sqlalchemy.engine.Engine [raw sql] ()
2025-08-20 23:18:18,839 INFO sqlalchemy.engine.Engine select current_schema()
2025-08-20 23:18:18,840 INFO sqlalchemy.engine.Engine [raw sql] ()
2025-08-20 23:18:18,841 INFO sqlalchemy.engine.Engine show standard_conforming_strings
2025-08-20 23:18:18,841 INFO sqlalchemy.engine.Engine [raw sql] ()
2025-08-20 23:18:18,842 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2025-08-20 23:18:18,844 INFO sqlalchemy.engine.Engine SELECT pg_catalog.pg_class.relname 
FROM pg_catalog.pg_class JOIN pg_catalog.pg_namespace ON pg_catalog.pg_namespace.oid = pg_catalog.pg_class.relnamespace 
WHERE pg_catalog.pg_class.relname = $1::VARCHAR AND pg_catalog.pg_class.relkind = ANY (ARRAY[$2::VARCHAR, $3::VARCHAR, $4::VARCHAR, $5::VARCHAR, $6::VARCHAR]) AND pg_catalog.pg_table_is_visible(pg_catalog.pg_class.oid) AND pg_catalog.pg_namespace.nspname != $7::VARCHAR
2025-08-20 23:18:18,844 INFO sqlalchemy.engine.Engine [generated in 0.00013s] ('items', 'r', 'p', 'f', 'v', 'm', 'pg_catalog')
2025-08-20 23:18:18,848 INFO sqlalchemy.engine.Engine COMMIT
2025-08-20 23:18:18,849 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2025-08-20 23:18:18,849 INFO sqlalchemy.engine.Engine SELECT pg_catalog.pg_class.relname 
FROM pg_catalog.pg_class JOIN pg_catalog.pg_namespace ON pg_catalog.pg_namespace.oid = pg_catalog.pg_class.relnamespace 
WHERE pg_catalog.pg_class.relname = $1::VARCHAR AND pg_catalog.pg_class.relkind = ANY (ARRAY[$2::VARCHAR, $3::VARCHAR, $4::VARCHAR, $5::VARCHAR, $6::VARCHAR]) AND pg_catalog.pg_table_is_visible(pg_catalog.pg_class.oid) AND pg_catalog.pg_namespace.nspname != $7::VARCHAR
2025-08-20 23:18:18,849 INFO sqlalchemy.engine.Engine [cached since 0.005799s ago] ('items', 'r', 'p', 'f', 'v', 'm', 'pg_catalog')
2025-08-20 23:18:18,851 INFO sqlalchemy.engine.Engine 
CREATE TABLE items (
        name VARCHAR NOT NULL, 
        item_id UUID NOT NULL, 
        created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL, 
        updated_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL, 
        collection_id VARCHAR NOT NULL, 
        PRIMARY KEY (item_id)
)


2025-08-20 23:18:18,851 INFO sqlalchemy.engine.Engine [no key 0.00012s] ()
2025-08-20 23:18:18,861 INFO sqlalchemy.engine.Engine CREATE INDEX ix_items_item_id ON items (item_id)
2025-08-20 23:18:18,861 INFO sqlalchemy.engine.Engine [no key 0.00014s] ()
2025-08-20 23:18:18,862 INFO sqlalchemy.engine.Engine COMMIT
2025-08-20 23:18:18,865 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2025-08-20 23:18:18,866 INFO sqlalchemy.engine.Engine INSERT INTO items (name, item_id, collection_id) VALUES ($1::VARCHAR, $2::UUID, $3::VARCHAR) RETURNING items.created_at, items.updated_at
2025-08-20 23:18:18,866 INFO sqlalchemy.engine.Engine [generated in 0.00017s] ('This is an item', UUID('c220c7ba-d4ed-455b-97a0-2a54b4dd9a11'), 'default')
2025-08-20 23:18:18,868 INFO sqlalchemy.engine.Engine COMMIT
2025-08-20 23:18:18,870 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2025-08-20 23:18:18,870 INFO sqlalchemy.engine.Engine INSERT INTO items (name, item_id, collection_id) VALUES ($1::VARCHAR, $2::UUID, $3::VARCHAR), ($4::VARCHAR, $5::UUID, $6::VARCHAR) RETURNING items.created_at, items.updated_at, items.item_id
2025-08-20 23:18:18,871 INFO sqlalchemy.engine.Engine [generated in 0.00010s (insertmanyvalues) 1/1 (ordered)] ('This is item 1', UUID('32c57d06-801a-40ea-8ec1-db7f00452e69'), 'default', 'This is item 2', UUID('79a54fc0-6c0c-4550-b022-bacf11b43bfa'), 'default')
2025-08-20 23:18:18,872 INFO sqlalchemy.engine.Engine COMMIT
2025-08-20 23:18:18,873 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2025-08-20 23:18:18,874 INFO sqlalchemy.engine.Engine SELECT pg_catalog.pg_class.relname 
FROM pg_catalog.pg_class JOIN pg_catalog.pg_namespace ON pg_catalog.pg_namespace.oid = pg_catalog.pg_class.relnamespace 
WHERE pg_catalog.pg_class.relname = $1::VARCHAR AND pg_catalog.pg_class.relkind = ANY (ARRAY[$2::VARCHAR, $3::VARCHAR, $4::VARCHAR, $5::VARCHAR, $6::VARCHAR]) AND pg_catalog.pg_table_is_visible(pg_catalog.pg_class.oid) AND pg_catalog.pg_namespace.nspname != $7::VARCHAR
2025-08-20 23:18:18,874 INFO sqlalchemy.engine.Engine [cached since 0.03023s ago] ('items', 'r', 'p', 'f', 'v', 'm', 'pg_catalog')
2025-08-20 23:18:18,875 INFO sqlalchemy.engine.Engine 
DROP TABLE items
2025-08-20 23:18:18,875 INFO sqlalchemy.engine.Engine [no key 0.00009s] ()
2025-08-20 23:18:18,878 INFO sqlalchemy.engine.Engine COMMIT