CQRS for Great Good - Amazon Simple Storage...

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CQRS for Great Good Oliver Wolf Donnerstag, 16. Mai 13

Transcript of CQRS for Great Good - Amazon Simple Storage...

Page 1: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRS for Great Good

Oliver Wolf

Donnerstag, 16. Mai 13

Page 2: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Oliver Wolf@owolf

www.innoQ.com@innoQ

Donnerstag, 16. Mai 13

Page 3: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRS

Donnerstag, 16. Mai 13

Page 4: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRSCommand Query Responsibility Segregation

Donnerstag, 16. Mai 13

Page 5: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The default architecture for distributed business apps

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findCustomers()getCustomer()updateCustomer()

<customer><name>John Doe</name><address>...</address>...

</customer>

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Page 7: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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GET /customers?filter=...GET /customer/{id}PUT /customer/{id}

{ "name": “John Doe”, "address": { ... }}

Donnerstag, 16. Mai 13

Page 8: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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GET /customers?filter=...GET /customer/{id}PUT /customer/{id}

{ "name": “John Doe”, "address": { ... }}

Anything wrong with this?

Donnerstag, 16. Mai 13

Page 9: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Maybe not.

Donnerstag, 16. Mai 13

Page 10: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Scalability?

Donnerstag, 16. Mai 13

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Domain Model?

Donnerstag, 16. Mai 13

Page 12: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Text

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Page 13: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Bertrand MeyerETH Zurich

Text

Donnerstag, 16. Mai 13

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“The features that characterize a class are divided

into commands and queries. A command serves to modify objects, a query to

return information about objects.”

Bertrand MeyerETH Zurich

Text

cited from: Object-Oriented Software Construction, second edition, 1997Donnerstag, 16. Mai 13

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CQSCommand Query Separation

Donnerstag, 16. Mai 13

Page 16: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Part of the Design-by-Contract methodology

First demonstrated in the object-oriented EIFFEL programming language

Donnerstag, 16. Mai 13

Page 17: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

class Foo { void command(); Result query();}

Donnerstag, 16. Mai 13

Page 18: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

class Foo { void command(); Result query();}

Mutates state

Donnerstag, 16. Mai 13

Page 19: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

class Foo { void command(); Result query();}

Mutates state

Returns a value without causing

side effects

Donnerstag, 16. Mai 13

Page 20: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRS=

CQS in the large

Donnerstag, 16. Mai 13

Page 21: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRS=

CQS in the largeScope is a

single classDonnerstag, 16. Mai 13

Page 22: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRS=

CQS in the largeScope is a

single class

Scope is a Bounded Context

Donnerstag, 16. Mai 13

Page 23: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

interface CustomerService {void updateCustomer(Customer);CustomerList findCustomers(CustomerQuery);Customer getCustomer(ID);void deleteCustomer(ID);

}

Donnerstag, 16. Mai 13

Page 24: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

interface CustomerQueryService {CustomerList findCustomers(CustomerQuery);Customer getCustomer(ID);

}

interface CustomerCommandService {void updateCustomer(Customer);void deleteCustomer(ID);

}

Donnerstag, 16. Mai 13

Page 25: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The default architecture for distributed business apps

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Page 26: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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CQRS PATTERN APPLIED

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That’s it?You

serious???

Donnerstag, 16. Mai 13

Page 29: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Yes, sorry.

Donnerstag, 16. Mai 13

Page 30: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The interesting thing about CQRS is not the pattern itself.

Donnerstag, 16. Mai 13

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It’s damn simple, actually.

Donnerstag, 16. Mai 13

Page 32: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

But it allows you to challenge established assumptions and opens up new architectural

options!

Donnerstag, 16. Mai 13

Page 33: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Unlearn what you

have learned

you must.

Donnerstag, 16. Mai 13

Page 34: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:Reads and Writes are

strongly cohesive, so they must be part of the same

Bounded Context.

Donnerstag, 16. Mai 13

Page 35: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:Reads and Writes are

strongly cohesive, so they must be part of the same

Bounded Context.FALSE

Donnerstag, 16. Mai 13

Page 36: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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CQRSified

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The default architecture for distributed business appsCQRSified

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Domain Model

Command and query parts can scale independently, e.g. to accommodate highly asymmetric load.

Donnerstag, 16. Mai 13

Page 38: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:Reads and writes use the

same data, so they must be served from and applied to the same domain model.

Donnerstag, 16. Mai 13

Page 39: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:Reads and writes use the

same data, so they must be served from and applied to the same domain model.

FALSE

Donnerstag, 16. Mai 13

Page 40: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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Query Model

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Page 41: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The default architecture for distributed business appsCQRSified

Queries can benefit from a specialized query model, optimized for quick data retrieval (de-normalized, pre-aggregated,...)

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Page 42: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The default architecture for distributed business appsCQRSified

Queries can benefit from a specialized query model, optimized for quick data retrieval (de-normalized, pre-aggregated,...)

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Query Model

‣ validate and process commands‣ keep data consistent‣ guarantee ACID properties‣ behaviour of domain model‣ more difficult to scale

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Page 43: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The default architecture for distributed business appsCQRSified

Queries can benefit from a specialized query model, optimized for quick data retrieval (de-normalized, pre-aggregated,...)

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‣ validate and process commands‣ keep data consistent‣ guarantee ACID properties‣ behaviour of domain model‣ more difficult to scale

‣ rich query capabilities‣ short response times‣ different views on data‣ potentially denormalized‣ easier to scale

Donnerstag, 16. Mai 13

Page 44: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:For queries, we have to use a

domain model to abstract from the underlying data

model.

Donnerstag, 16. Mai 13

Page 45: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:For queries, we have to use a

domain model to abstract from the underlying data

model.FALSE

Donnerstag, 16. Mai 13

Page 46: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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SELECT … FROM … WHERE ...

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Page 47: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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Queries are just dealing with data, not with behavior. Why do we need objects?

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Page 48: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:We must use the same

database for queries and commands to make sure that

data is consistent.

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Page 49: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:We must use the same

database for queries and commands to make sure that

data is consistent.FALSE

Donnerstag, 16. Mai 13

Page 50: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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SELECT … FROM … WHERE ...

QueryDBQuery

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Page 51: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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In many cases, eventual consistency is sufficient. The data users are looking at in the UI is always stale to some extent.

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Page 52: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:Commands must be

processed immediately to ensure data consistency.

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Page 53: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:Commands must be

processed immediately to ensure data consistency.FALSE

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Page 54: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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Page 55: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

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In many cases, users don’t care whether their actions have immediate effect – as long as they eventually get feedback.

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Page 56: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

The default architecture for distributed business appsCQRSified

In many cases, users don’t care whether their actions have immediate effect – as long as they eventually get feedback.

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update read model asynchronously

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Page 57: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:The current state of domain objects must be persistent.

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Page 58: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Assumption:The current state of domain objects must be persistent.FALSE

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The default architecture for distributed business appsCQRSified

Donnerstag, 16. Mai 13

Page 60: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Quer

y Ser

vices

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terfa

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Quer

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Quer

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Command Model

Quer

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Quer

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SELECT … FROM … WHERE ...

QueryDBQuery

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The default architecture for distributed business appsCQRSified

CQRS plays well with an Event Sourcing architecture – you just store events and re-create the state of domain objects as needed.

Donnerstag, 16. Mai 13

Page 61: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Quer

y Ser

vices

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d La

yerUs

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terfa

ce

Quer

y Fac

ade

Quer

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Com

man

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man

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Command Model

Quer

y Fac

ade

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SELECT … FROM … WHERE ...

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The default architecture for distributed business appsCQRSified

CQRS plays well with an Event Sourcing architecture – you just store events and re-create the state of domain objects as needed.

event store

Donnerstag, 16. Mai 13

Page 62: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Event Sourcing in a nutshell

Donnerstag, 16. Mai 13

Page 63: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ capture each update to application state in an event

Event Sourcing in a nutshell

Donnerstag, 16. Mai 13

Page 64: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ capture each update to application state in an event

‣ changes to domain objects are the result of applying events

Event Sourcing in a nutshell

Donnerstag, 16. Mai 13

Page 65: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ capture each update to application state in an event

‣ changes to domain objects are the result of applying events

‣ events are immutable

Event Sourcing in a nutshell

Donnerstag, 16. Mai 13

Page 66: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ capture each update to application state in an event

‣ changes to domain objects are the result of applying events

‣ events are immutable

‣ events are a representation of what has happened at a specific time

Event Sourcing in a nutshell

Donnerstag, 16. Mai 13

Page 67: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

What’s so great about Event Sourcing?

Donnerstag, 16. Mai 13

Page 68: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ allows you to rebuild application state at any point in time just by replaying events up to that point in time

What’s so great about Event Sourcing?

Donnerstag, 16. Mai 13

Page 69: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ allows you to rebuild application state at any point in time just by replaying events up to that point in time

‣ allows you to analyse historic data based on detailed events that would otherwise have been lost

What’s so great about Event Sourcing?

Donnerstag, 16. Mai 13

Page 70: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ allows you to rebuild application state at any point in time just by replaying events up to that point in time

‣ allows you to analyse historic data based on detailed events that would otherwise have been lost

‣ gives you an audit log “for free”

What’s so great about Event Sourcing?

Donnerstag, 16. Mai 13

Page 71: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

‣ allows you to rebuild application state at any point in time just by replaying events up to that point in time

‣ allows you to analyse historic data based on detailed events that would otherwise have been lost

‣ gives you an audit log “for free”

‣ you can add new, optimized read models (potentially in-memory) later without migration hassle and such

What’s so great about Event Sourcing?

Donnerstag, 16. Mai 13

Page 72: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

That’s it. Really.Feel free to ask me anything!

@owolfhttp://www.flickr.com/photos/kaptainkobold/5170454747/

How do I convince by boss that we’ll

have to rewrite our application with

CQRS???

Donnerstag, 16. Mai 13

http://www.flickr.com/photos/kaptainkobold/5170454747/
http://www.flickr.com/photos/kaptainkobold/5170454747/
Page 73: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

You probably don’t.

Donnerstag, 16. Mai 13

Page 74: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

CQRS is not a silver bullet and doesn’t apply everywhere.

Beware of the added complexity!

Donnerstag, 16. Mai 13

Page 75: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Don’t do CQRS…

Donnerstag, 16. Mai 13

Page 76: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Don’t do CQRS…

…if your application is just a simple CRUD-style app.

Donnerstag, 16. Mai 13

Page 77: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Don’t do CQRS…

…if your application is just a simple CRUD-style app.

…if you don’t have scaling issues.

Donnerstag, 16. Mai 13

Page 78: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Don’t do CQRS…

…if your application is just a simple CRUD-style app.

…if you don’t have scaling issues.

…if it doesn’t improve your domain models.

Donnerstag, 16. Mai 13

Page 79: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Consider doing CQRS…

…if your write/read load ratio is highly asymmetrical.

…if scaling your application is difficult.

…if your domain model is bloated by complex domain logic, making queries inefficient.

…if you can benefit from event sourcing.

Donnerstag, 16. Mai 13

Page 80: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Frameworks, any?

Donnerstag, 16. Mai 13

Page 81: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Axon Framework (Java)www.axonframework.org

Piotr Wyczesany

Donnerstag, 16. Mai 13

Page 82: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Axon Framework (Java)www.axonframework.org

Piotr Wyczesany

Lokad (.NET)http://lokad.github.com/lokad-cqrs/

Piotr Wyczesany

Donnerstag, 16. Mai 13

Page 83: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Axon Framework (Java)www.axonframework.org

Piotr Wyczesany

Lokad (.NET)http://lokad.github.com/lokad-cqrs/

Piotr Wyczesany

…and some morePiotr Wyczesany

Donnerstag, 16. Mai 13

Page 84: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

Axon Framework (Java)www.axonframework.org

Piotr Wyczesany

Lokad (.NET)http://lokad.github.com/lokad-cqrs/

Piotr Wyczesany

…and some morePiotr Wyczesany

Piotr Wyczesany

DDD/CQRS/ES in practice – Axon to the rescue

Today, 11:40amRoom 1

Donnerstag, 16. Mai 13

Page 85: CQRS for Great Good - Amazon Simple Storage Services3-eu-west-1.amazonaws.com/presentations2013/77_presentation.pdf · Part of the Design-by-Contract methodology First demonstrated

That’s it. Really.Feel free to ask me anything!

@owolfDonnerstag, 16. Mai 13


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