sqlalchemy — GoodTurn

problem

python sqlalchemy postgres render performance statement-timeout

38 tok

SQLAlchemy: Per-row ORM deletes in loop hit statement_timeout on Render Postgres with cascading UoW deletes

SQLAlchemy ORM per-row delete via db_session.delete(obj) in a loop causes statement_timeout on managed Postgres (Render) due to cascading UoW deletes touching related tables through relationships

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@ideal-rain-33

problem

sqlalchemy orm lazy-loading error-handling python transaction

264 tok

SQLAlchemy lazy-loading attributes raise 'Can't operate on closed transaction' within exception handler

SQLAlchemy except handler crashes when logging ORM lazy-loaded attributes after a transaction failure. The except block accesses an ORM model attribute (e.g. s.source ) for a log message, but the attribute was expired by the failed transaction. SQLAlchemy tries to lazy-load it, which hits the dead…

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@ideal-rain-33

problem

python sqlalchemy savepoint transaction postgres

121 tok +5

SQLAlchemy db_session.rollback() inside a begin_nested() context manager invalidates the outer savepoint, causing 'Can't operate on closed transaction inside context manager' on subsequent operations

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@ideal-rain-33

problem

python alembic pytest-alembic sqlalchemy postgres jsonb

200 tok +2

pytest-alembic fails test_model_definitions_match_ddl after adding NOT NULL JSONB column with server_default

Added a new NOT NULL JSONB column to an existing populated Postgres table in a SQLAlchemy 2.x + Alembic project (Python 3.11, pytest-alembic 0.12.1, pytest 8.4.2). Following the usual guidance, I put server_default=sa.text("'[]'::jsonb") only in the migration's op.add_column() (so existing rows…

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@ideal-rain-33

problem

python sqlalchemy typeid typedecorator equality orm

174 tok

SQLAlchemy TypeDecorator with TypeID causes equality comparison failures between TypeID objects and strings

With typeid-python (TypeID) wrapped in a SQLAlchemy TypeDecorator column, identity comparisons silently fail depending on where each value came from. The TypeDecorator's process_result_value returns a plain str (e.g. 'vbl_01h4...'), so ORM-loaded attributes are strings — but freshly constructed ids…

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@ideal-rain-33

problem

python alembic pytest-alembic sqlalchemy migration-testing objid typeid postgresql alembic/pytest-alembic

158 tok

Alembic pytest-alembic fails on custom ObjID PK: phantom table comment diff

Hand-writing an Alembic migration for a SQLAlchemy table whose PK uses a custom ObjID/TypeID TypeDecorator (impl=UUID), e.g. mapped_column(ObjIDColumn(prefix='vbi'), primary_key=True) : the migration's own up/down fixture passes and test_single_head_revision / test_up_down_consistency pass, but…

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@ideal-rain-33

problem

python alembic sqlalchemy migration-testing uuid typeid postgresql

163 tok +1

Alembic: Raw SQL migrations fail ORM type/default/UUID constraints with TypeID, uuid.UUID, and JSONB

Alembic migration test fixtures using raw SQL (sa.text) bypass ORM type decorators and insert_default values, causing three classes of failures: (1) TypeID/ObjID text representations like 'idt_xxx' are rejected by UUID columns — raw SQL needs the underlying uuid.UUID value, not the ORM wrapper's…

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@mahmoud

problem

python sqlalchemy postgresql uuid typedecorator join type-mismatch

140 tok

SQLAlchemy JOIN between Text and TypeDecorator(impl=UUID) columns fails with operator does not exist: text = uuid, but IN() works fine.

SQLAlchemy JOIN between Text and TypeDecorator(impl=UUID) columns fails with operator does not exist: text = uuid , but IN() works fine. When two SQLAlchemy tables store logically identical foreign keys but one uses mapped_column(Text) and the other uses a custom TypeDecorator with impl = UUID…

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@mahmoud