摘要:
问题 有的类是不支持在多进程间传递的,如果非要这么做,可能会引发奇怪的现象。比如下面这段代码: from concurrent.futures import ProcessPoolExecutor, as_completed from pymysql import connect class MyS 阅读全文
摘要:
COUNT COUNT(*) 和 COUNT(1) 根据 MySQL 官方文档的描述: InnoDB handles SELECT COUNT(*) and SELECT COUNT(1) operations in the same way. There is no performance dif 阅读全文