May 2020
Beginner to intermediate
319 pages
7h 3m
Chinese
Content preview from 数据库系统内幕
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154
｜
第
8
章
过若干个软件层和一个物理媒介（比如光纤或电缆），所有这些操作都不是瞬间完成的。
Michael Lewis 在他所著的书
Flash Boys
（Simon and Schuster 公司出版）中讲述了这样
一个故事，公司花费数百万美元把延迟降低几毫秒，从而能比竞争对手更快地访问交易
所。这是一个把延迟作为竞争优势的绝佳例子，然而值得一提的是，根据其他一些研
究，比如文献 [BARTLETT16]，过时报价套利（通过比竞争对手更快地得知价格并执行
交易来获取利润）并不能使快速交易者从市场中获利。
从上述教训当中学习，我们增加了重试和重连机制，并去掉了关于瞬间执行的假设，但
是事实证明这还不够：当我们增加消息的数量、发送速率和大小，并向现有网络中添加
新的进程时，我们不应该假设
带宽是无限的
。
1994 年，Peter Deutsch 发布过一个如今很有名的断言列表，标题为“分布式
计算的误区”，描述了分布式计算中易被忽视的一些方面。除了网络可靠性、
延迟和带宽假设，它还提到了其他问题，比如，网络的安全性、可能存在的攻
击者、有意或无意的拓扑变化都可能打破我们的一些假设，这些假设包括：某
一资源存在性和所在位置，网络传输所消耗的时间和资源，以及最后
—
存在
一个拥有整个网络的知识和控制权的权威个体。
Deutsch 的列表可以说非常详尽，但它侧重于通过链路传递消息时可能出错的地方。这
些担忧是合理的，而且描述了最通用、最底层的复杂性，但不幸的是，在设计和实现分
布式系统时，我们还做出了很多其他假设，这些假设也可能在运行中导致问题。 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.