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
Data Migration with Confidence
Search
Juanito Fatas
June 22, 2017
Programming
3
910
Data Migration with Confidence
At RedDotRubyConf 2017
Juanito Fatas
June 22, 2017
Tweet
Share
More Decks by Juanito Fatas
See All by Juanito Fatas
My Open Source Journey
juanitofatas
1
3.2k
NSDanger
juanitofatas
1
170
How to build deppbot
juanitofatas
3
590
Introducing Danger
juanitofatas
0
320
Twemoji 3.0 in the making and announcement beyond SG50
juanitofatas
0
760
Continuous Updates
juanitofatas
0
140
Ruby Asia and dat bacon cannon
juanitofatas
1
260
Update Early, Update Often
juanitofatas
1
1.1k
RSpec for Practical Rubyist
juanitofatas
11
830
Other Decks in Programming
See All in Programming
他言語経験者が Golangci-lint を最初のコーディングメンターにした話 / How Golangci-lint Became My First Coding Mentor: A Story from a Polyglot Programmer
uma31
0
330
The Past, Present, and Future of Enterprise Java
ivargrimstad
0
380
Catch Up: Go Style Guide Update
andpad
0
240
Flutterで分数(Fraction)を表示する方法
koukimiura
0
140
コード生成なしでモック処理を実現!ovechkin-dm/mockioで学ぶメタプログラミング
qualiarts
0
240
Domain-centric? Why Hexagonal, Onion, and Clean Architecture Are Answers to the Wrong Question
olivergierke
3
940
Leading Effective Engineering Teams in the AI Era
addyosmani
7
560
EMこそClaude Codeでコード調査しよう
shibayu36
0
300
20251016_Rails News ~Rails 8.1の足音を聴く~
morimorihoge
2
660
Google Opalで使える37のライブラリ
mickey_kubo
3
130
Six and a half ridiculous things to do with Quarkus
hollycummins
0
210
釣り地図SNSにおける有料機能の実装
nokonoko1203
0
190
Featured
See All Featured
Facilitating Awesome Meetings
lara
56
6.6k
Build your cross-platform service in a week with App Engine
jlugia
232
18k
Principles of Awesome APIs and How to Build Them.
keavy
127
17k
Making Projects Easy
brettharned
120
6.4k
Intergalactic Javascript Robots from Outer Space
tanoku
273
27k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
52
5.7k
Context Engineering - Making Every Token Count
addyosmani
7
280
Why Our Code Smells
bkeepers
PRO
340
57k
Building a Modern Day E-commerce SEO Strategy
aleyda
44
7.8k
Art, The Web, and Tiny UX
lynnandtonic
303
21k
Optimizing for Happiness
mojombo
379
70k
Connecting the Dots Between Site Speed, User Experience & Your Business [WebExpo 2025]
tammyeverts
10
610
Transcript
Data Migration with Confidence Juanito Fatas RedDotRubyConf 2017
@JuanitoFatas Ramen Specialist
Spanish name From Taiwan Live in Tokyo
I became a salaryman #
Cookpad Global Cookpad Japan
Made in Japan $
Reserve for local jokes %
Data Migration?
Schema Migration Data Migration
Schema Migration Alter Schemas over time https://en.wikipedia.org/wiki/Schema_migration
Data Migration https://en.wikipedia.org/wiki/Data_migration Transfer data from to A System B
System
Existing Data Migration
None
Data Migration to Existing System
Data Migration with Confidence @JuanitoFatas Specialist of cookpad RedDotRubyConf 2017
Why Migration?
Rewrote for Clients
New Partner joins company
Data Migration
~ Get All Data to our system Simple Goal
~ Import data Modeling Migrate After migrate
~ Get the Data Provider API Data Dump
Provider API & Generic Migration Code ✅
Data Dump & Generic Migration Code
HOWTO Data Migration
~ Start with a rake task
~
~ lib/tasks/data_migration.rake
~ lib/data_migration.rb
~ Import dump to local
~ GBs-size file
monthly users 62 30M countries ~
~ Add delay to the SQL dump for production
~ Add sleep() before INSERT INTO
~ Editing huge file
~ +
~
~ Enumerable#lazy https://ruby-doc.org/core-2.4.1/Enumerable.html#method-i-lazy
~
~
~ set accordingly for staging & production
~ Modeling Database
~
~ With these 5 methods, you can model anything.
~ Map data to your current system
~ Sometimes as easy as
~ As HTML in the recipes table field ‘steps’ ,
Sometimes…
~
~
~ Setup Test Suite
~
~
~ - Why Tests? The migration code only used once
~ Better code through boring tests
~ TDD to Get Things Done
~ Modeling Tests Repeat
Migration
~ Use all methods that raises exception
~ Fail Fast to find all errors
~ Example Migrate Recipes
~
~
None
~
~ Add more migrators to migrate
~ Data Integrity
~ Transaction
~ Idempotent Operation
~
~ Run Migration many times
~ Produce the Same Result
~ f(x) = f(x)
~ Upsert Update or Insert
~ MySQL ON DUPLICATE KEY UPDATE PostgreSQL ON CONFLICT UPDATE
PostgreSQL 9.5+ seamusabshere/upsert
~
~ Data Accuracy
~ Manually Check
~ Automated Check
~ Example Check users with most Recipes
~
~
~
~
~
~ To check more things Add more Checker objects
~ Use many small objects to compose
~ Objects Everywhere
For better object design
For better object design
Background Jobs
Workers = CPU cores
Designated Queues
None
None
Log Every Unexpected Error
None
None
For Better handling of Errors
Run against all data to be migrated
Fix every error you can before real migration
~ Tools
Retry mechanism
Foreign Key Constraints Locks
MySQL deadlock Results in
Automatic Retry # Rails 4: ActiveRecord::StatementInvalid
Make sure what should be Retry
retry_on discard_on ActiveJob::Exceptions
Automatic Retry
Examine & Retry
In Resque
None
Status Reporting
None
None
Report every minute
Monitoring CPU Usage
None
~ Performance
Performance is a Rabbit hole
Preload associations
Minimize scope of transaction
Transaction Isolation Levels https://dev.mysql.com/doc/refman/5.7/en/innodb-transaction-isolation-levels.html https://www.postgresql.org/docs/current/static/transaction-iso.html
Avoid unnecessary callbacks
None
Example You can touch http://api.rubyonrails.org/classes/ActiveRecord/NoTouching/ClassMethods.html#method-i-no_touching after migration
Process multiple records in one job
None
Cache data in Memory
Cache data in Redis
Migrate Important things first
First 10000 users w/ most recipes
IO bound
Scale up the Database
Decrease the workers /0
Bulk Insert Bulk Upsert* * Only MySQL supports bulk upsert
zdennis/activerecord-import
Every change to make it fast
Run the WHOLE migration again
Keep CPU usage max at 75% all
~ Post Migration
Update all necessities
Redirects
Redirect tables Cookpad Redirect programs Server redirects Provider
Redirection Service cookpad/mirin
~ Stories
Cases of Email
Remove duplicate emails before migration
Remove invalid emails before migration
downcase all the emails
~ Get Site Dump
~ 100GB generated on EC2* EC2 has bandwidth limits
~ scp takes days ONLY if nothing failed within days
~ delivers encrypted disk
Migrate Millions of records
AR + transaction bulk in/upsert activerecord-import load data in file
Weeks Month-ish
Run low priority job to migrate them
When migrated User signed in
Migrate their data in high priority
None
Migrate 100K photos
How our image work
Design so it produces the same hash 4
Set the designated hash during migration instead of upload, generate
hash
Benchmark how long to finish all
X days?
Migrate them X days before in low priority
99% photos won’t change
Migrate users password to secure auth
Figure out what algorithm(s) was(ere) used
When migrated user signed in
System’s password auth will fail
Fallback to Legacy Auth
None
When password matched from legacy auth
Set his password through secure password scheme
None
Migration ~ The Future
Migration done in Ghost Table fashion
Data Dump & Generic Migration Code Only need to modeling
database
~ Takeaways
Rails provides sharp tools thanks to rails core team
Use Small objects to make your code more readable &
maintainable
Abstraction is the God of Programming! “ ” — Matthew
Mongeau @halogenandtoast
Schedule >> Fast
Schedule >> Fast Integrity >> schedule
Data Migration sounds hard
Keep it Simple Made it Easy
Do the Simplest Things “ ” — Winston Teo Yon
Wei @winstonyw
Enjoy ☕ Thank you!