beyond crud: patterns that never forget
TRANSCRIPT
Beyond CRUD:patterns that never forget
Diego Moreno
· R&D Software Manager @ Bizpills Group
· Now making a new platform
easy, fast, collaborative & scalable
Rise your hand if you have
· heard about CQRS/Event Sourcing
Rise your hand if you have
· heard about CQRS/Event Sourcing
· used it in production
Rise your hand if you have
· heard about CQRS/Event Sourcing
· used it in production
· heard about Redux
Big data trees
Our need: Make fast & scalable
reads, writes and copies
Problem: read fast or write fast
but not both
Challenge
[Recurso gráfico: caja de herramientas semivacía]
Business logic
backend
frontend
TipicalWeb App
backend
frontend
CQRS:Command Query
Responsibility Segregation
Commandlogic
Querylogic
THINKOUTSIDETHEBOX
Read and write from same source?
THINKOUTSIDETHEBOX
backend
frontend
CQRS:Command Query
Responsibility Segregation
Commandlogic
Querylogic
backend
frontend
CQRS:Command Query
Responsibility Segregation
sync orasync
deriveddata
Commandlogic
Querylogic
CQRS: Derived data
◼ Application-level
▼ Race conditions
▼ Cold start
▼ Cache miss ratio
▼ Invalidation
Cache
CQRS: Derived data
◼ Application-level
▼ Race conditions
▼ Cold start
▼ Cache miss ratio
▼ Invalidation
◼ Database-level
▲ Autosync
▼ Additional load on database
▼ Limited to SQL logic
▼ Code testing/maintenance
Cache Materialized Views
backend
frontend
CQRS:Command Query
Responsibility Segregation
sync orasync
deriveddata
Commandlogic
Querylogic
backend
views
frontend
view generator
CQRS
Commandlogic
Querylogic
CQRS: Pros & Cons
▲ Separation of concerns
▲ Optimize reads & writes
▲ No cold cache
▲ No race conditions
▲ Agile development
▲ Scale reads & writesindependently
CQRS: Pros & Cons
▲ Separation of concerns
▲ Optimize reads & writes
▲ No cold cache
▲ No race conditions
▲ Agile development
▲ Scale reads & writesindependently
▼ Complexity
▼ UX impact
Read and write from same source?
THINKOUTSIDETHEBOX
Read and write from same source?
Data must be mutable?
THINKOUTSIDETHEBOX
A
1 32
node parent
1 A
2 A
Event Sourcing
Don’t save current state
Save the events that lead to current state
A
1 32
node parent
1 A
2 A
event node parent
ADD_CHILD 1 A
ADD_CHILD 2 A
ADD_CHILD 3 A
REMOVE_CHILD 3 A
Event Sourcing
CRUDCreate Read Update Delete
CRUDCreate Read Update Delete
ES: Pros & Cons
▲ Fast-write
▲ Deal with immutable data
▲ Easy audit
▲ Recovery from human error
▲ Users can undo actions
▲ Better analytics
ES: Pros & Cons
▲ Fast-write
▲ Deal with immutable data
▲ Easy audit
▲ Recovery from human error
▲ Users can undo actions
▲ Better analytics
▼ Complexity
▼ Event backward compatibility
▼ No current state
▼ Slow-read
backend
views
frontend
view generator
CQRS
Commandlogic
Querylogic
backend
views
frontend
view generator
a
a
ES + CQRS
action log
a
Commandlogic
Querylogic
Redux
REDUCERS STATE
actions subscribe
change State container written in Javascript
UI dispatch actions
Only reducers change state
backend
views
frontend
view generator
a
a
ES + CQRS
action log
a
Commandlogic
Querylogic
backend
views
frontend
view generator
a
Redux + ES + CQRS
action log
a
Commandlogic
Querylogic
Re
Sta
Commandlogic
Querylogic
Re
St
Re St
backend
action log
views
frontend
a
a
a
view generator
Redux + ES + CQRS
Redux: Pros & Cons
▲ Predictable state changes
▲ Optimistic UI
▲ Desktop app performance
▲ “undo” UI
Redux: Pros & Cons
▲ Predictable state changes
▲ Optimistic UI
▲ Desktop app performance
▲ “undo” UI
▼ Learning curve
Commandlogic
Querylogic
Re
St
Re St
backend
action log
views
frontend
a
a
a
view generator
Redux + ES + CQRS
Commandlogic
Querylogic
Re
St
Re St
backend
action log
views
frontend
a
a
a
a
view generator
Redux + ES + CQRSreal time collaboration
web socket
Real life
backend
views
frontend
view generatoraction log
Commandlogic
Querylogic
backend
views
frontend
view generatoraction log
Commandlogic
Querylogic
Alternative: Apache Samza
backend
frontend
view generatoraction log
Commandlogic
Querylogic
views
backend
frontend
view generatoraction log
Commandlogic
Querylogic
views
backend
views
frontend
view generatoraction log
Commandlogic
Querylogic
Alternative: Apache Kafka
CQRS + ES + Redux
▲ Fast
▲ Collaborative
▲ Scalable
▼ Complexity
“a great power comes a great
responsibility”
“a great power comes a great
responsibility”
[Recurso gráfico: caja de herramientas repleta de cosas o
banco de bricolaje lleno de herramientas]
Thanks
ReferencesMartin Kleppmann @ Strange Loop 2014: Turning the database inside-out with Apache Samzahttps://www.confluent.io/blog/turning-the-database-inside-out-with-apache-samza/
Kevin Robinson @ React Europe 2015: Simplifying the data layer at react-europe 2015https://www.youtube.com/watch?v=EOz4D_714R8
Martin Fowler: CQRShttp://martinfowler.com/bliki/CQRS.htm