2018-07-04 SQLAlchemy批量插入性能比较

转载自:
SQLAlchemy批量插入性能比较

import time
import sqlite3
 
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String,  create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
 
Base = declarative_base()
DBSession = scoped_session(sessionmaker())
engine = None
 
 
class Customer(Base):
    __tablename__ = "customer"
    id = Column(Integer, primary_key=True)
    name = Column(String(255))
 
 
def init_sqlalchemy(dbname='sqlite:///sqlalchemy.db'):
    global engine
    engine = create_engine(dbname, echo=False)
    DBSession.remove()
    DBSession.configure(bind=engine, autoflush=False, expire_on_commit=False)
    Base.metadata.drop_all(engine)
    Base.metadata.create_all(engine)
 
 
def test_sqlalchemy_orm(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    for i in xrange(n):
        customer = Customer()
        customer.name = 'NAME ' + str(i)
        DBSession.add(customer)
        if i % 1000 == 0:
            DBSession.flush()
    DBSession.commit()
    print(
        "SQLAlchemy ORM: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")
 
 
def test_sqlalchemy_orm_pk_given(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    for i in xrange(n):
        customer = Customer(id=i+1, name="NAME " + str(i))
        DBSession.add(customer)
        if i % 1000 == 0:
            DBSession.flush()
    DBSession.commit()
    print(
        "SQLAlchemy ORM pk given: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")
 
 
def test_sqlalchemy_orm_bulk_save_objects(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    n1 = n
    while n1 > 0:
        n1 = n1 - 10000
        DBSession.bulk_save_objects(
            [
                Customer(name="NAME " + str(i))
                for i in xrange(min(10000, n1))
            ]
        )
    DBSession.commit()
    print(
        "SQLAlchemy ORM bulk_save_objects(): Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")
 
def test_sqlalchemy_orm_bulk_insert(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    n1 = n
    while n1 > 0:
        DBSession.bulk_insert_mappings(
            Customer,
            [
                dict(name="NAME " + str(i))
                for i in xrange(min(10000, n1))
            ]
        )
        n1 = n1 - 10000
    DBSession.commit()
    print(
        "SQLAlchemy ORM bulk_insert_mappings(): Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")
 
def test_sqlalchemy_core(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    engine.execute(
        Customer.__table__.insert(),
        [{"name": 'NAME ' + str(i)} for i in xrange(n)]
    )  ##==> engine.execute('insert into ttable (name) values ("NAME"), ("NAME2")')
    print(
        "SQLAlchemy Core: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")
 
 
def init_sqlite3(dbname):
    conn = sqlite3.connect(dbname)
    c = conn.cursor()
    c.execute("DROP TABLE IF EXISTS customer")
    c.execute(
        "CREATE TABLE customer (id INTEGER NOT NULL, "
        "name VARCHAR(255), PRIMARY KEY(id))")
    conn.commit()
    return conn
 
 
def test_sqlite3(n=100000, dbname='sqlite3.db'):
    conn = init_sqlite3(dbname)
    c = conn.cursor()
    t0 = time.time()
    for i in xrange(n):
        row = ('NAME ' + str(i),)
        c.execute("INSERT INTO customer (name) VALUES (?)", row)
    conn.commit()
    print(
        "sqlite3: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " sec")
 
if __name__ == '__main__':
    test_sqlalchemy_orm(100000)
    test_sqlalchemy_orm_pk_given(100000)
    test_sqlalchemy_orm_bulk_save_objects(100000)
    test_sqlalchemy_orm_bulk_insert(100000)
    test_sqlalchemy_core(100000)
    test_sqlite3(100000)

上面代码分别使用了orm， orm带主键，orm的bulk_save_objects, orm的bulk_insert_mappings, 非orm形式，原生的dbapi方式；插入10000条记录的结果如下：

SQLAlchemy ORM: Total time for 100000 records 7.2070479393 secs
SQLAlchemy ORM pk given: Total time for 100000 records 4.28471207619 secs
SQLAlchemy ORM bulk_save_objects(): Total time for 100000 records 1.58296084404 secs
SQLAlchemy ORM bulk_insert_mappings(): Total time for 100000 records 0.453973054886 secs
SQLAlchemy Core: Total time for 100000 records 0.210998058319 secs
sqlite3: Total time for 100000 records 0.136252880096 sec

注意：
这里只有第一、二种方式可以拿到插入记录的id，其它都不能直接拿到，需要自己再查询一次。

原文连接：http://docs.sqlalchemy.org/en/latest/faq/performance.html