scrapy异步存储mysql大量数据库

MYSQL_HOST = 'localhost'
MYSQL_PORT = 3306
MYSQL_USER = 'root'
MYSQL_PASSWORD = 'password'
MYSQL_DB = 'database_name'

import pymysql

class MySQLPipeline(object):
    def __init__(self, host, port, user, password, database):
        self.host = host
        self.port = port
        self.user = user
        self.password = password
        self.database = database

    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            host=crawler.settings.get('MYSQL_HOST'),
            port=crawler.settings.get('MYSQL_PORT'),
            user=crawler.settings.get('MYSQL_USER'),
            password=crawler.settings.get('MYSQL_PASSWORD'),
            database=crawler.settings.get('MYSQL_DB'),
        )

    def open_spider(self, spider):
        self.connection = pymysql.connect(
            host=self.host,
            port=self.port,
            user=self.user,
            password=self.password,
            database=self.database,
            charset='utf8mb4'
        )
        self.cursor = self.connection.cursor()

    def close_spider(self, spider):
        self.connection.close()

    def process_item(self, item, spider):
        # 异步将数据插入数据库
        sql = "INSERT INTO table_name (field1, field2) VALUES (%s, %s)"
        self.cursor.execute(sql, (item['field1'], item['field2']))
        self.connection.commit()
        return item

ITEM_PIPELINES = {
   'myproject.pipelines.MySQLPipeline': 300,
}