理解公制运动的探索

Charles Wu, Software Engineer | Isabel Tallam, Software Engineer | Franklin Shiao, Software Engineer | Kapil Bajaj, Engineering Manager

Charles Wu, 软件工程师 | Isabel Tallam, 软件工程师 | Franklin Shiao, 软件工程师 | Kapil Bajaj, 工程经理

Overview

概述

Suppose you just saw an interesting rise or drop in one of your key metrics. Why did that happen? It’s an easy question to ask, but much harder to answer.

假设您刚刚看到您的某个关键指标出现了有趣的上升或下降。这是为什么呢？这是一个容易提出的问题，但要回答却要困难得多。

One of the key difficulties in finding root causes for metric movements is that these causes can come in all shapes and sizes. For example, if your metric dashboard shows users experiencing higher latency as they scroll through their home feed, then that could be caused by anything from an OS upgrade, a logging or data pipeline error, an unusually large increase in user traffic, a code change landed recently, etc. The possible reasons go on and on.

寻找指标变动根本原因的一个关键困难在于，这些原因可能有各种形状和大小。例如，如果您的指标仪表板显示用户在浏览主页时体验到更高的延迟，那么这可能是由操作系统升级、日志或数据管道错误、用户流量异常增加、最近的代码更改等引起的。可能的原因不胜枚举。

At Pinterest, we have built different quantitative models to understand why metrics move the way they do. This blog outlines the three pragmatic approaches that form the basis of the root-cause analysis (RCA) platform at Pinterest. As you will see, all three approaches try to narrow down the search space for root causes in different ways.

在 Pinterest，我们建立了不同的定量模型来理解指标为何以特定方式变化。本文概述了构成 Pinterest 根本原因分析 (RCA) 平台基础的三种务实方法。正如您所看到的，这三种方法都试图以不同的方式缩小根本原因的搜索空间。

Figure 1: Narrowing down the search space for root causes.

图1：缩小根本原因的搜索范围。

Slice and Dice

切片与切块

This approach finds clues for a metric movement by drilling down on specific segments within the metric; it has found successes at Pinterest, especially in diagnosing video metric regressions.

这种方法通过深入分析指标内的特定段落来寻找指标变动的线索；它在Pinterest取得了成功，尤其是在诊断视频指标回归方面。

For example, suppose we are monitoring video view rate (i.e., number of views over impressions). At Pinterest, a metric like video view rate is multidimensional: it has many dimensions like country, device type, Pin type, ...