examples.performance.bulk_inserts — SQLAlchemy 1.2 Documentation

Release: 1.2.19 | Release Date: April 15, 2019

# SQLAlchemy 1.2 Documentation

# Source code for examples.performance.bulk_inserts

    """This series of tests illustrates different ways to INSERT a large number
    of rows in bulk.

    """
    from sqlalchemy import bindparam
    from sqlalchemy import Column
    from sqlalchemy import create_engine
    from sqlalchemy import Integer
    from sqlalchemy import String
    from sqlalchemy.ext.declarative import declarative_base
    from sqlalchemy.orm import Session
    from . import Profiler

    Base = declarative_base()
    engine = None

    class Customer(Base):
        __tablename__ = "customer"
        id = Column(Integer, primary_key=True)
        name = Column(String(255))
        description = Column(String(255))

    Profiler.init("bulk_inserts", num=100000)

    @Profiler.setup
    def setup_database(dburl, echo, num):
        global engine
        engine = create_engine(dburl, echo=echo)
        Base.metadata.drop_all(engine)
        Base.metadata.create_all(engine)

    @Profiler.profile
    def test_flush_no_pk(n):
        """Individual INSERT statements via the ORM, calling upon last row id"""
        session = Session(bind=engine)
        for chunk in range(0, n, 1000):
            session.add_all(
                [
                    Customer(
                        name="customer name %d" % i,
                        description="customer description %d" % i,
                    )
                    for i in range(chunk, chunk + 1000)
                ]
            )
            session.flush()
        session.commit()

    @Profiler.profile
    def test_bulk_save_return_pks(n):
        """Individual INSERT statements in "bulk", but calling upon last row id"""
        session = Session(bind=engine)
        session.bulk_save_objects(
            [
                Customer(
                    name="customer name %d" % i,
                    description="customer description %d" % i,
                )
                for i in range(n)
            ],
            return_defaults=True,
        )
        session.commit()

    @Profiler.profile
    def test_flush_pk_given(n):
        """Batched INSERT statements via the ORM, PKs already defined"""
        session = Session(bind=engine)
        for chunk in range(0, n, 1000):
            session.add_all(
                [
                    Customer(
                        id=i + 1,
                        name="customer name %d" % i,
                        description="customer description %d" % i,
                    )
                    for i in range(chunk, chunk + 1000)
                ]
            )
            session.flush()
        session.commit()

    @Profiler.profile
    def test_bulk_save(n):
        """Batched INSERT statements via the ORM in "bulk", discarding PKs."""
        session = Session(bind=engine)
        session.bulk_save_objects(
            [
                Customer(
                    name="customer name %d" % i,
                    description="customer description %d" % i,
                )
                for i in range(n)
            ]
        )
        session.commit()

    @Profiler.profile
    def test_bulk_insert_mappings(n):
        """Batched INSERT statements via the ORM "bulk", using dictionaries."""
        session = Session(bind=engine)
        session.bulk_insert_mappings(
            Customer,
            [
                dict(
                    name="customer name %d" % i,
                    description="customer description %d" % i,
                )
                for i in range(n)
            ],
        )
        session.commit()

    @Profiler.profile
    def test_core_insert(n):
        """A single Core INSERT construct inserting mappings in bulk."""
        conn = engine.connect()
        conn.execute(
            Customer.__table__.insert(),
            [
                dict(
                    name="customer name %d" % i,
                    description="customer description %d" % i,
                )
                for i in range(n)
            ],
        )

    @Profiler.profile
    def test_dbapi_raw(n):
        """The DBAPI's API inserting rows in bulk."""

        conn = engine.pool._creator()
        cursor = conn.cursor()
        compiled = (
            Customer.__table__.insert()
            .values(name=bindparam("name"), description=bindparam("description"))
            .compile(dialect=engine.dialect)
        )

        if compiled.positional:
            args = (
                ("customer name %d" % i, "customer description %d" % i)
                for i in range(n)
            )
        else:
            args = (
                dict(
                    name="customer name %d" % i,
                    description="customer description %d" % i,
                )
                for i in range(n)
            )

        cursor.executemany(str(compiled), list(args))
        conn.commit()
        conn.close()

    if __name__ == "__main__":
        Profiler.main()