sqlalchemy/examples/performance/short_selects.py

"""This series of tests illustrates different ways to SELECT a single
record by primary key


"""

import random

from sqlalchemy import bindparam
from sqlalchemy import Column
from sqlalchemy import create_engine
from sqlalchemy import Identity
from sqlalchemy import Integer
from sqlalchemy import select
from sqlalchemy import String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.future import select as future_select
from sqlalchemy.orm import deferred
from sqlalchemy.orm import Session
from . import Profiler


Base = declarative_base()
engine = None

ids = range(1, 11000)


class Customer(Base):
    __tablename__ = "customer"
    id = Column(Integer, Identity(), primary_key=True)
    name = Column(String(255))
    description = Column(String(255))
    q = Column(Integer)
    p = Column(Integer)
    x = deferred(Column(Integer))
    y = deferred(Column(Integer))
    z = deferred(Column(Integer))


Profiler.init("short_selects", num=10000)


@Profiler.setup
def setup_database(dburl, echo, num):
    global engine
    engine = create_engine(dburl, echo=echo, query_cache_size=0)
    Base.metadata.drop_all(engine)
    Base.metadata.create_all(engine)
    sess = Session(engine)
    sess.add_all(
        [
            Customer(
                id=i,
                name="c%d" % i,
                description="c%d" % i,
                q=i * 10,
                p=i * 20,
                x=i * 30,
                y=i * 40,
            )
            for i in ids
        ]
    )
    sess.commit()


@Profiler.profile
def test_orm_query_classic_style(n):
    """classic ORM query of the full entity, no cache"""
    session = Session(bind=engine)
    for id_ in random.sample(ids, n):
        session.query(Customer).filter(Customer.id == id_).one()


@Profiler.profile
def test_orm_query_classic_style_w_cache(n):
    """classic ORM query of the full entity, using cache"""
    cache = {}
    session = Session(bind=engine.execution_options(compiled_cache=cache))
    for id_ in random.sample(ids, n):
        session.query(Customer).filter(Customer.id == id_).one()


@Profiler.profile
def test_orm_query_new_style(n):
    """new style ORM select() of the full entity, no cache."""

    session = Session(bind=engine)
    for id_ in random.sample(ids, n):
        stmt = future_select(Customer).where(Customer.id == id_)
        session.execute(stmt).scalar_one()


@Profiler.profile
def test_orm_query_new_style_cache(n):
    """new style ORM select() of the full entity, using cache."""

    cache = {}
    session = Session(bind=engine.execution_options(compiled_cache=cache))
    for id_ in random.sample(ids, n):
        stmt = future_select(Customer).where(Customer.id == id_)
        session.execute(stmt).scalar_one()


@Profiler.profile
def test_orm_query_classic_style_cols_only(n):
    """classic ORM query against columns, no cache"""
    session = Session(bind=engine)
    for id_ in random.sample(ids, n):
        session.query(Customer.id, Customer.name, Customer.description).filter(
            Customer.id == id_
        ).one()


@Profiler.profile
def test_orm_query_classic_style_cols_only_cache(n):
    """classic ORM query against columns, using cache"""
    cache = {}
    session = Session(bind=engine.execution_options(compiled_cache=cache))
    for id_ in random.sample(ids, n):
        session.query(Customer.id, Customer.name, Customer.description).filter(
            Customer.id == id_
        ).one()


@Profiler.profile
def test_core_new_stmt_each_time(n):
    """test core, creating a new statement each time, no cache"""

    with engine.connect() as conn:
        for id_ in random.sample(ids, n):
            stmt = select(Customer.__table__).where(Customer.id == id_)
            row = conn.execute(stmt).first()
            tuple(row)


@Profiler.profile
def test_core_new_stmt_each_time_compiled_cache(n):
    """test core, creating a new statement each time, using cache"""

    compiled_cache = {}
    with engine.connect().execution_options(
        compiled_cache=compiled_cache
    ) as conn:
        for id_ in random.sample(ids, n):
            stmt = select(Customer.__table__).where(Customer.id == id_)
            row = conn.execute(stmt).first()
            tuple(row)


@Profiler.profile
def test_core_reuse_stmt(n):
    """test core, reusing the same statement, no cache"""

    stmt = select(Customer.__table__).where(Customer.id == bindparam("id"))
    with engine.connect() as conn:
        for id_ in random.sample(ids, n):
            row = conn.execute(stmt, {"id": id_}).first()
            tuple(row)


@Profiler.profile
def test_core_reuse_stmt_compiled_cache(n):
    """test core, reusing the same statement, using cache"""

    stmt = select(Customer.__table__).where(Customer.id == bindparam("id"))
    compiled_cache = {}
    with engine.connect().execution_options(
        compiled_cache=compiled_cache
    ) as conn:
        for id_ in random.sample(ids, n):
            row = conn.execute(stmt, {"id": id_}).first()
            tuple(row)


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