摘要：参考：https://blog.csdn.net/bugzeroman/article/details/103031317 阅读全文

摘要：MySQL https://blog.csdn.net/Abysscarry/article/details/80792876 阅读全文

摘要：https://www.moonfly.net/archives/66.html Messages in the "maildrop", "hold", "incoming" and "deferred" queues (see below) do not occupy memory; they a 阅读全文