August 2019
Beginner to intermediate
232 pages
3h 50m
Chinese
Content preview from Web容量规划之美
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.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.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.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.
88
第
3
章
规划数据库，特别是数据库集群，可能是一件棘手的事情。确定数据库的性能上
限是非常困难的，因为可能有些隐藏的极端问题仅在一些边界情况下才会暴露出
来。
例如，过去我们在
Flickr
做过一个假设，在性能开始衰减到我们不能接受之前，
在给定的硬件平台上，数据库每秒可以处理
X
个查询的上限值，但是我们惊讶地
发现，对于那些少于
10000
张照片的用户，一些查询性能很好，而对于那些超过
100000
张照片的用户却出奇的慢（是的，一些
Flickr
用户上传无数张照片）。因此，
我们为处理有大量照片用户的数据库服务器重新定义了上限。这种对容量和性能
进行创造性的调查对数据库来说是必须的，并且强调了，在系统统计数据的角度
之外，理解数据库的实际使用情况的重要性。
在这个阶段，我重申我们关于性能调优的观点。正如
Jeremy Zawodny
和
Derek
Balling
在《
High Performance MySQL
》一书提到的那样，数据库的性能通常更多
依赖于你的模式和查询而不是硬件的速度。因此，开发者和数据库管理员，致力
于优化他们的方案和查询，因为他们知道这样做可以相当明显地改变数据库的性
能。相反，则会影响到数据库性能的上限。某一天你认为你需要
10
个数据库服务
器来支持每秒
20000
个查询；另外一天你发现你只需要
5
个，这是因为开发人员
能够优化一些更常见（或计算开销较大）的查询。
一个真实的示例：数据库测量
数据库是复杂的，要找到数据库的上限是很耗时的，但也是很有价值的。就像
Web
服务器，数据库的容量往往也是峰值驱动的 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.