Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
PWL NY: Simple Testing Can Prevent Most Critica...
Search
Caitie McCaffrey
June 14, 2016
Technology
8
440
PWL NY: Simple Testing Can Prevent Most Critical Failures
Caitie McCaffrey
June 14, 2016
Tweet
Share
More Decks by Caitie McCaffrey
See All by Caitie McCaffrey
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
330
21k
The Path Towards Simplifying Consistency in Distributed Systems
caitiem20
1
290
Argus Papers We Love
caitiem20
13
1.2k
The Verification of a Distributed System
caitiem20
22
2.2k
We Hear You Like Papers: Eventual Consistency
caitiem20
14
790
The Verification of a Distributed System
caitiem20
12
750
The Verification of a Distributed System
caitiem20
6
750
A Brief History of Distributed Programming: RPC
caitiem20
31
6.5k
Building Scalable Stateful Services
caitiem20
12
1.5k
Other Decks in Technology
See All in Technology
CNAPPから考えるAWSガバナンスの実践と最適化
nrinetcom
PRO
1
330
Oracle Cloud Infrastructure:2025年1月度サービス・アップデート
oracle4engineer
PRO
0
180
カスタムインストラクションでGitHub Copilotをカスタマイズ!
07jp27
4
260
ソフトウェアアーキテクトのための意思決定術: Software Architecture and Decision-Making
snoozer05
PRO
17
4k
DevSecOps入門:Security Development Lifecycleによる開発プロセスのセキュリティ強化
yuriemori
0
230
Grafanaのvariables機能について
tiina
0
180
Creative Pair
kawaguti
PRO
1
130
地方企業がクラウドを活用するヒント
miu_crescent
PRO
1
110
Skip Skip Run Run Run ♫
temoki
0
360
[SRE kaigi 2025] ガバメントクラウドに向けた開発と変化するSRE組織のあり方 / Development for Government Cloud and the Evolving Role of SRE Teams
kazeburo
4
1.9k
サーバーレスで楽しよう!お気軽に始められる3つのポイント / Have fun with Serverless!
_kensh
2
220
ブロックチェーンR&D企業における SREの実態 / SRE Kaigi 2025
datachain
0
3.9k
Featured
See All Featured
Java REST API Framework Comparison - PWX 2021
mraible
28
8.4k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
3
270
CoffeeScript is Beautiful & I Never Want to Write Plain JavaScript Again
sstephenson
160
15k
Building a Modern Day E-commerce SEO Strategy
aleyda
38
7.1k
The Power of CSS Pseudo Elements
geoffreycrofte
75
5.4k
The Pragmatic Product Professional
lauravandoore
32
6.4k
StorybookのUI Testing Handbookを読んだ
zakiyama
28
5.4k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
507
140k
Learning to Love Humans: Emotional Interface Design
aarron
274
40k
Fantastic passwords and where to find them - at NoRuKo
philnash
50
3k
Building a Scalable Design System with Sketch
lauravandoore
460
33k
Raft: Consensus for Rubyists
vanstee
137
6.7k
Transcript
Simple Testing Can Prevent Most Critical Failures: An Analysis of
Production Failures in Distributed Data-Intensive Systems Papers We Love New York - June 2016
Caitie McCaffrey @caitie Distributed Systems Engineer CaitieM.com
None
None
Analyzed Failures in Real World Systems
“A majority (77%) of failures require more than one input
event to manifest, but most of the failures (90%) require no more than 3” Complexity of Failures
“The specific order of events is important in 88% of
the failures that require multiple events Complexity of Failures
“3 Nodes or less can reproduce 98% of Failures” Complexity
of Failures
Unit Tests “A majority of production failures (77%) can be
reproduced by a unit test”
Top Down Fault Injection & State Space Exploration is Expensive
Logging • 76% of the failures print explicit failure- related
error messages • For 84% of the failures, all of the triggering events are logged • Logs are noisy: each failure prints 824 log messages (median)
Catastrophic Failures
Error Handling • 92% of failures were the result of
incorrect handling of non-fatal errors • 58% of faults could have been detected via simple testing • 35% of failures caused by bad practices in error handling code
• Error Handling Code is simply empty or only contains
a Log statement • Error Handler aborts cluster on an overly general exception • Error Handler contains comments like FIXME or TODO Bad Practices
Aspirator Performs static analysis of Java bytecode to detect: •
error handler is empty • error handler over-catches exceptions and aborts • error handler contains phrases like “TODO” or “FIXME”
• 500 New Bugs & Bad Practices • 115 Fasle
Positives • 171 bugs reported • 143 bugs confirmed or fixed Aspirator Results
-developer “I fail to see the reason to handle every
exception” Developer Reactions
“It is often much harder to reason about the correctness
of a system’s abnormal path than its normal execution path ”
Moving Forward • Use a tool like Aspirator that is
capable of identifying trivial bugs • Enforce code reviews of error handling code • High code coverage on error handling code
Questions @caitie