如何使用多进程池和cx_oracle运行并行查询

import multiprocessing
import cx_Oracle

pool = multiprocessing.Pool(processes=4)  # 这里设置进程池的大小为4，可以根据实际情况进行调整

def query(sql):
    conn = cx_Oracle.connect("username/password@host:port/service_name")  # 这里填写Oracle数据库的连接信息
    cursor = conn.cursor()
    cursor.execute(sql)
    result = cursor.fetchall()
    cursor.close()
    conn.close()
    return result

def callback(result):
    # 处理查询结果
    print(result)

sql_list = ["SELECT * FROM table1", "SELECT * FROM table2", "SELECT * FROM table3"]  # 这里填写需要查询的SQL语句
for sql in sql_list:
    pool.apply_async(query, args=(sql,), callback=callback)

pool.close()
pool.join()