August 2019
Beginner to intermediate
232 pages
3h 50m
Chinese
Content preview from Web容量规划之美
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139
趋势预测
这意味着对于你选择的特定数据库查询，你可以在命中数据库前访问缓存。这样
做主要为了两个目标：加速高频查询和减少高频查询带来的数据库服务负载。
这样做最显著的好处是，过去需要花费数秒的查询通过缓存查询只需要短短几毫
秒，这意味着你的
Web
服务器能够快速返回客户端的响应。这样做有一个副作用：
当用户不需要等待页面时，会出现更快单击链接的倾向，导致
Web
服务器上的负
载增加。
memcached
的部署很快就演变成
Web
服务器的容量问题，这很常见。
长期趋势
现在你知道了如何应用第
3
章收集的统计数据到当前需求，但是当你看产品和网
站策略相关问题时，但你也可能想从一个更全球化的角度来看待你的网站，无论
是从字面意义上看（作为一个国际流行网站）还是从图像上。
流量模式变更
如前所述，了解各种资源和应用程序的使用量的高峰期和低谷期对于预测未来是
非常重要的。当你获取到越来越多度量指标的历史信息，你就能察觉更细微的趋势，
它将告诉你长期的结果。例如，让我们看看图
4-16
，它展示了一个
Web
服务器的
典型流量模式。
图
4-16
展示了一个非常典型的某国每日的流量模式。在某地区时间的早上随着用
户开始浏览，负载缓慢增长。这些用户在其他地区用户开始上线的时候去吃午饭，
负载保持不变，最终在人们下班后下降。这里负载降到只有那些通宵浏览的用户
带来的负载。
随着用户量的增加，你可以预计到该图会随着更多用户在同一峰值和低谷访问网
站，变得更加垂直化，但是如果你的用户变得更国际化，你每天看到的流量峰值
会随着活跃用户时钟区域的增加变得更宽。如图
4-16
所示，如果你的网站在比某
地区更远的区域更受欢迎的话，你甚至可能看到在某国用户都不访问后出现典型
的流量峰值。
140
第
4
章
图
4
-
16
：典型的每日 Web 服务器流量模式
图
4-17
展示了两个相隔一年的日流量模式，你 ...
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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.