← Extractions

Event Sourcing Anti-Patterns & Failures — Nathan Ladd at wroclove.rb 2018

Nathan Ladd's wroclove.rb 2018 talk walks through event-sourcing basics (commands, handlers, projections, events) and then dissects four common anti-patterns: entities coupled to messaging, view-biased event schemas, opaque dependencies (hidden projections and opaque writers), and the aggregate-root-as-god-class pattern. He closes with meta-advice about scrutinizing community thought leaders, treating complexity as contextualized, and spending a week or two on real up-front design before coding.

Model

claude-opus-4-7

Ingestion

43cc404e

Input tokens

226,664

fresh: 115,868
cached: 96,419
cache write: 14,377

Output tokens

15,489

Duration

244.2s

Roundtrips

Tool calls

Cost

$0.00

Nodes/edges extracted

33 / 51

Read set (nodes/edges)

97 / 36

Nodes (33)

update Event Sourcing Anti Patterns and Failures talk

attrs {"type" => "talk"} → {"date" => "2018-03-16", "type" => "talk"}

description Talk at wroclove.rb 2018. → Nathan Ladd's wroclove.rb 2018 talk, delivered as the first event-sourcing talk of the conference. Opens with a revie...

short_description Talk at wroclove.rb 2018. → Nathan Ladd's wroclove.rb 2018 talk on common event-sourcing anti-patterns and failure modes.

update Nathan Ladd person

attrs (empty) → {"role" => "co-principal, Eventide project", "twitter" => "@realntl"}

description Conference speaker. At wroclove.rb 2018 gave a talk critiquing aggregates and their coupling to events, which signifi... → Conference speaker, co-principal / co-founder of the Eventide project (a toolkit for event sourcing and autonomous se...

short_description Ruby conference speaker, Eventide co-maintainer. → Ruby conference speaker; co-principal of the Eventide project.

create Command Message concept

kind (empty) → concept

name (empty) → Command Message

slug (empty) → command-message

attrs (empty) → {"category" => "pattern"}

description (empty) → Ladd's generalized name for a web form or any input handled by an MVC controller: a command message. In event-sourced...

short_description (empty) → A message expressing intent — a generalized name for a web form or controller input.

create Command Handler concept

kind (empty) → concept

name (empty) → Command Handler

slug (empty) → command-handler

attrs (empty) → {"category" => "pattern"}

description (empty) → Component that receives a command message, projects the relevant entity, accepts or rejects the command (usually via ...

short_description (empty) → Entry-point component that receives a command and decides which event(s) to write.

create Entity Projection concept

kind (empty) → concept

name (empty) → Entity Projection

slug (empty) → entity-projection

attrs (empty) → {"category" => "pattern"}

description (empty) → In event sourcing, projecting an entity means reading its stream sequentially starting from a blank/empty data struct...

short_description (empty) → Folding an event stream from empty state into a single entity representation.

create Entity Coupled To Messaging concept

kind (empty) → concept

name (empty) → Entity Coupled To Messaging

slug (empty) → entity-coupled-to-messaging

attrs (empty) → {"category" => "pattern"}

description (empty) → First anti-pattern in Ladd's talk. When an entity method takes a command message as a parameter, decodes its attribut...

short_description (empty) → Anti-pattern: entities that accept command messages, interpret them, and return events.

create View-Biased Event Schemas concept

kind (empty) → concept

name (empty) → View-Biased Event Schemas

slug (empty) → view-biased-event-schemas

attrs (empty) → {"category" => "pattern"}

description (empty) → Second anti-pattern. When building materialized views from events, teams are tempted to shove UI-only data (e.g. cate...

short_description (empty) → Anti-pattern: shaping events to carry UI/view fields rather than raw facts.

create Opaque Dependencies concept

kind (empty) → concept

name (empty) → Opaque Dependencies

slug (empty) → opaque-dependencies

attrs (empty) → {"category" => "pattern"}

description (empty) → Third anti-pattern. Dependencies are 'opaque' when the handler can't see or control them. Two flavors discussed: (1) ...

short_description (empty) → Anti-pattern: hiding projections, writers or other dependencies the handler should control.

create Aggregate Root Anti-Pattern concept

kind (empty) → concept

name (empty) → Aggregate Root Anti-Pattern

slug (empty) → aggregate-root-anti-pattern

attrs (empty) → {"category" => "pattern"}

description (empty) → Fourth anti-pattern in Ladd's talk. A class that mixes entity business logic, command handling, and event projection ...

short_description (empty) → Anti-pattern: a single class mixing entity, handler, and projection responsibilities.

create Reservation Pattern concept

kind (empty) → concept

name (empty) → Reservation Pattern

slug (empty) → reservation-pattern

attrs (empty) → {"category" => "pattern"}

description (empty) → Event-sourcing technique Ladd cites for enforcing uniqueness (e.g. of an email address): write a reservation event ke...

short_description (empty) → Uniqueness validation in event-sourced systems via a reservation event on the shared key.

create Expected Version concept

kind (empty) → concept

name (empty) → Expected Version

slug (empty) → expected-version

attrs (empty) → {"category" => "pattern"}

description (empty) → Optimistic concurrency countermeasure when writing to an event store: the write specifies the expected current versio...

short_description (empty) → Concurrency control parameter on event-store writes used to detect and reject races.

create Vector Clock concept

kind (empty) → concept

name (empty) → Vector Clock

slug (empty) → vector-clock

attrs (empty) → {"category" => "architecture"}

description (empty) → Technical mechanism Ladd names for ordering events produced by distributed systems where a simple timestamp is unreli...

short_description (empty) → Causal-ordering mechanism for events across distributed systems.

create Entity Caching and Snapshotting concept

kind (empty) → concept

name (empty) → Entity Caching and Snapshotting

slug (empty) → entity-caching-and-snapshotting

attrs (empty) → {"category" => "practice"}

description (empty) → Because each event has a position exactly one greater than the previous, an entity projected up to position N can be ...

short_description (empty) → Performance countermeasures for event-stream replay: versioned entity cache and periodic snapshots.

create Contextualized Complexity concept

kind (empty) → concept

name (empty) → Contextualized Complexity

slug (empty) → contextualized-complexity

attrs (empty) → {"category" => "practice"}

description (empty) → Ladd's reframing of the complexity objection to moving off monoliths. Yes, partitioning and event sourcing add patter...

short_description (empty) → Complexity you add to a system but only deal with a small subset of at any time.

create Immutable Database Raises Mistake Cost takeaway

kind (empty) → takeaway

name (empty) → Immutable Database Raises Mistake Cost

slug (empty) → immutable-database-raises-mistake-cost

attrs (empty) → {"type" => "warning"}

description (empty) → Because the event store is immutable, correcting bad data is much harder than in a relational database (where you can...

short_description (empty) → Mistakes in event-sourced systems are far more expensive than in mutable databases.

create Keep Entities Free Of Messaging takeaway

kind (empty) → takeaway

name (empty) → Keep Entities Free Of Messaging

slug (empty) → keep-entities-free-of-messaging

attrs (empty) → {"type" => "recommendation"}

description (empty) → Recommendation: entities should contain only core business logic and be readable as a specification of the domain. Th...

short_description (empty) → Entities should be pure domain logic, not aware of commands or events.

create Events Record What Occurred, Nothing Else takeaway

kind (empty) → takeaway

name (empty) → Events Record What Occurred, Nothing Else

slug (empty) → events-record-what-occurred-nothing-else

attrs (empty) → {"type" => "recommendation"}

description (empty) → Don't bend event schemas to accommodate UI needs. Adding UI-derived fields (e.g. a category_id computed from a heuris...

short_description (empty) → Never add view-only fields to events to make UI composition easier.

create Handlers Must Control Their Dependencies takeaway

kind (empty) → takeaway

name (empty) → Handlers Must Control Their Dependencies

slug (empty) → handlers-must-control-their-dependencies

attrs (empty) → {"type" => "recommendation"}

description (empty) → Handlers must be able to control the projection (for caching, snapshotting, or to skip it entirely) and the writer (t...

short_description (empty) → Command handlers should own their projection and writer, not delegate to framework.

create Don't Conflate Entity, Handler and Projection takeaway

kind (empty) → takeaway

name (empty) → Don't Conflate Entity, Handler and Projection

slug (empty) → don-t-conflate-entity-handler-and-projection

attrs (empty) → {"type" => "recommendation"}

description (empty) → Avoid the aggregate-root-as-god-class pattern. Keeping entity, handler, and projection as separate classes preserves ...

short_description (empty) → Keep entities, handlers, and projections as separate, independently testable classes.

create Scrutinize Community Thought Leaders takeaway

kind (empty) → takeaway

name (empty) → Scrutinize Community Thought Leaders

slug (empty) → scrutinize-community-thought-leaders

attrs (empty) → {"type" => "insight"}

description (empty) → Communities have positive connotations and can achieve wonders (Ladd's Amish barn-raising and Texas hurricane example...

short_description (empty) → Communities and leaders can suppress critical thinking; hold popular ideas under scrutiny.

create A Week Of Up-Front Design Is Not Waterfall takeaway

kind (empty) → takeaway

name (empty) → A Week Of Up-Front Design Is Not Waterfall

slug (empty) → a-week-of-up-front-design-is-not-waterfall

attrs (empty) → {"type" => "recommendation"}

description (empty) → 'Measure twice, cut once.' The move from waterfall to agile replaced 6–18 months of up-front design, but the communit...

short_description (empty) → Closing the laptop to design a service for a week is agile, not waterfall.

create Tooling Never Forced Your Monolith takeaway

kind (empty) → takeaway

name (empty) → Tooling Never Forced Your Monolith

slug (empty) → tooling-never-forced-your-monolith

attrs (empty) → {"type" => "warning"}

description (empty) → Teams that move from Rails to event sourcing sometimes build the same god classes they criticised Rails for. Switchin...

short_description (empty) → Don't blame Rails (or any tool) for your god classes — and don't expect Elixir to fix them.

create Entity Store tool

kind (empty) → tool

name (empty) → Entity Store

slug (empty) → entity-store

attrs (empty) → {"category" => "library"}

description (empty) → One of the 30+ libraries in the Eventide project. Provides projection of entities from event streams, along with an e...

short_description (empty) → Eventide Ruby library implementing entity projection with cache and snapshotting.

create What is an entity? question

kind (empty) → question

name (empty) → What is an entity?

slug (empty) → what-is-an-entity

attrs (empty) → {"answer_summary" => "Primarily a data structure with domain-specific methods; logically, a whole microservice can al...

description (empty) → Audience asks whether an entity is an object with attributes or a process. Ladd: usually a data structure with domain...

short_description (empty) → Q&A clarifying what Ladd means by 'entity' in event sourcing.

create Is the sufficient-funds check a feature envy smell? question

kind (empty) → question

name (empty) → Is the sufficient-funds check a feature envy smell?

slug (empty) → is-the-sufficient-funds-check-a-feature-envy-smell

attrs (empty) → {"answer_summary" => "The conditional belongs in the handler because deciding which event to write is a messaging con...

description (empty) → Audience member (citing 'tell don't ask') objects that the handler asks the account if there are sufficient funds, th...

short_description (empty) → Q&A on whether handler-side querying of the entity violates 'tell don't ask'.

create What is the biggest challenge with this approach? question

kind (empty) → question

name (empty) → What is the biggest challenge with this approach?

slug (empty) → what-is-the-biggest-challenge-with-this-approach

attrs (empty) → {"answer_summary" => "Prototyping speed — event-sourced services never match Rails' sketch-velocity, by design."}

description (empty) → Audience asks what Ladd's biggest current challenge is. Answer: you will never prototype as fast as with Rails. In ma...

short_description (empty) → Q&A on the biggest day-to-day pain of event-sourced services.

create How is the event-write kept consistent with external operations? question

kind (empty) → question

name (empty) → How is the event-write kept consistent with external operations?

slug (empty) → how-is-the-event-write-kept-consistent-with-external-operations

attrs (empty) → {"answer_summary" => "Either the service is authoritative (no external call), or the external call happens in the han...

description (empty) → Audience asks how recording 'withdrawn' stays consistent with the actual withdrawal when an external API (e.g. a wire...

short_description (empty) → Q&A on transactional integrity between event writes and external side effects.

create How do you order events across distributed systems? question

kind (empty) → question

name (empty) → How do you order events across distributed systems?

slug (empty) → how-do-you-order-events-across-distributed-systems

attrs (empty) → {"answer_summary" => "Vector clocks; but teach the underlying ordering problem first."}

description (empty) → Audience notes the event 'time' attribute is just metadata and doesn't imply ordering. They ask how events are ordere...

short_description (empty) → Q&A on event ordering without relying on wall-clock time.

create Do Rails adopters write handlers instead of controller actions? question

kind (empty) → question

name (empty) → Do Rails adopters write handlers instead of controller actions?

slug (empty) → do-rails-adopters-write-handlers-instead-of-controller-actions

attrs (empty) → {"answer_summary" => "Have the controller write a command message to a stream rather than handle it inline; that keep...

description (empty) → Audience asks whether Rails adopters end up writing command handlers instead of controller actions. Ladd: one of thei...

short_description (empty) → Q&A on how Rails teams integrate Eventide into their MVC.

create How do you deal with event versioning? question

kind (empty) → question

name (empty) → How do you deal with event versioning?

slug (empty) → how-do-you-deal-with-event-versioning

attrs (empty) → {"answer_summary" => "Hard problem. In monoliths, version events and branch on read. In microservices, rebuild the se...

description (empty) → Audience asks how to handle evolving event schemas. Ladd: it's a difficult situation. In a monolith, versioning is us...

short_description (empty) → Q&A on changing event schemas after events have been written.

create Centralised vs per-service event store? question

kind (empty) → question

name (empty) → Centralised vs per-service event store?

slug (empty) → centralised-vs-per-service-event-store

attrs (empty) → {"answer_summary" => "A shared physical event store is fine because streams are naturally isolated; split only for op...

description (empty) → Audience asks whether Eventide uses a centralised event store. Ladd: the 'one DB per service' rule comes from relatio...

short_description (empty) → Q&A on whether each microservice should own a separate event store.

create Do events store current state, and how does replay perform? question

kind (empty) → question

name (empty) → Do events store current state, and how does replay perform?

slug (empty) → do-events-store-current-state-and-how-does-replay-perform

attrs (empty) → {"answer_summary" => "Events are raw occurrences; current state is folded. Performance is handled via a version-keyed...

description (empty) → Audience asks whether each event stores the latest state or the change, and how performance is affected when state mu...

short_description (empty) → Q&A on whether events carry latest state and on projection performance.

create How do you deal with GDPR in an immutable event store? question

kind (empty) → question

name (empty) → How do you deal with GDPR in an immutable event store?

slug (empty) → how-do-you-deal-with-gdpr-in-an-immutable-event-store

attrs (empty) → {"answer_summary" => "Model regulatory requirements in the business domain; they aren't a framework concern. Ladd has...

description (empty) → Audience asks about GDPR-style data-protection requirements in immutable stores. Ladd quips that in America you can d...

short_description (empty) → Q&A on handling regulatory requirements like GDPR with event sourcing.

Edges (51)

update Event Sourcing Anti Patterns and Failures → presented_at → wroclove.rb 2018

context (empty) → Delivered as the first event-sourcing talk of wroclove.rb 2018.

update Nathan Ladd → authored → Event Sourcing Anti Patterns and Failures

context (empty) → Nathan Ladd presented the talk as a co-principal of Eventide.

create Nathan Ladd → attended → wroclove.rb 2018

context (empty) → Attended as a speaker.

relation (empty) → attended

source_node_id (empty) → c2047c7c-2316-4c38-af4f-1e8a78f80206

target_node_id (empty) → 9243ef2c-21bb-4f23-b450-9ecd87882dfe

update Nathan Ladd → works_on → Eventide

attrs {"role" => "co-maintainer"} → {"role" => "co-principal"}

context Garofolo names Nathan as co-maintainer of Eventide's Postgres-backed message store. → Co-principal / co-founder of the Eventide project.

update Scott Bell → works_on → Eventide

context Garofolo names Scott Bell as co-maintainer of Eventide's Postgres-backed message store alongside Nathan Ladd. → Ladd credits 'my colleague Scott' as co-builder and disabuser of his bad ideas.

create Event Sourcing Anti Patterns and Failures → about → Event Sourcing

context (empty) → Whole talk is about event sourcing and its anti-patterns.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 687c9da2-de87-4fb2-a758-c7498f394fd5

create Event Sourcing Anti Patterns and Failures → about → Command Message

context (empty) → Opens by reframing web forms and controller inputs as command messages.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 02772774-712b-4af2-9ec4-e4eafa94cb07

create Event Sourcing Anti Patterns and Failures → about → Command Handler

context (empty) → Describes MVC controllers as command handlers and argues handlers must own projection and writing.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → e72326d6-a168-47a5-a1f7-dea8b50d49e3

create Event Sourcing Anti Patterns and Failures → about → Entity Projection

context (empty) → Explains projection as folding an event stream into an entity, and warns against hiding it.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 28ae0d67-fcf9-4a6a-adb3-fb01e56cc520

create Event Sourcing Anti Patterns and Failures → about → Entity Coupled To Messaging

context (empty) → First anti-pattern covered.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 464fbf52-5421-4819-b59c-959db0f9d819

create Event Sourcing Anti Patterns and Failures → about → View-Biased Event Schemas

context (empty) → Second anti-pattern covered.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 1879d94d-1505-48d7-88f5-b6d45eca370a

create Event Sourcing Anti Patterns and Failures → about → Opaque Dependencies

context (empty) → Third anti-pattern, covering opaque projections and opaque writers.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → f7438446-2e23-45b0-a0df-81a1a77b29b8

create Event Sourcing Anti Patterns and Failures → about → Aggregate Root Anti-Pattern

context (empty) → Fourth anti-pattern — the 'friendly fight' Ladd picks.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → fd357908-6682-403f-9137-5349f516c23d

create Event Sourcing Anti Patterns and Failures → about → Reservation Pattern

context (empty) → Cited as a case where no entity is needed, so framework-forced entities are harmful.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → f4122a36-a471-4735-9d10-214ce1cba685

create Event Sourcing Anti Patterns and Failures → about → Expected Version

context (empty) → Used as the key example of why handlers must control their writers.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 7238ed7d-25a7-4b44-bb37-49843b6b2089

create Event Sourcing Anti Patterns and Failures → about → Contextualized Complexity

context (empty) → Closing argument that added patterns are contextualized complexity, not global complexity.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → c8f5c168-c804-4d98-be23-8a5f8d51ee71

create Event Sourcing Anti Patterns and Failures → about → Aggregate Root

context (empty) → Directly critiques the aggregate-root pattern and its use.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 09c37511-f144-42de-a3e8-abae18862f96

create Event Sourcing Anti Patterns and Failures → about → Event Store

context (empty) → Discusses writing to the event store, its immutability, and centralised-vs-per-service deployment.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 41e612ae-2c1f-4a3c-8690-d47ac47e0174

create Event Sourcing Anti Patterns and Failures → about → Entity Store

context (empty) → Sketched as the Eventide library providing entity projection with cache and snapshotting.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 111a5c90-99c8-44b7-8e32-b25d2b578053

create Event Sourcing Anti Patterns and Failures → about → Active Record

context (empty) → Uses MVC+ORM as the foil against which event sourcing is contrasted.

relation (empty) → about

source_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

target_node_id (empty) → 633eeea8-2026-4906-b512-1e239f3db152

create Entity Store → related_to → Eventide

context (empty) → entity_store is one of the ~30 libraries that make up the Eventide toolkit.

relation (empty) → related_to

source_node_id (empty) → 111a5c90-99c8-44b7-8e32-b25d2b578053

target_node_id (empty) → 702f4d95-01a7-4836-9562-8c14b01a4b73

create Immutable Database Raises Mistake Cost → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Explicit warning motivating avoidance of the anti-patterns.

relation (empty) → from_talk

source_node_id (empty) → 72063b7a-4126-4a2f-8f06-f06ed38f924a

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Keep Entities Free Of Messaging → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Recommendation from the first anti-pattern.

relation (empty) → from_talk

source_node_id (empty) → 2feaa423-a235-428f-9c49-522c9aa8e25d

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Events Record What Occurred, Nothing Else → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Recommendation from the second anti-pattern.

relation (empty) → from_talk

source_node_id (empty) → 68b76301-2620-41f1-9986-d1a4f5ca3553

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Handlers Must Control Their Dependencies → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Recommendation from the third anti-pattern.

relation (empty) → from_talk

source_node_id (empty) → 4db2dafc-effc-4b7f-a2fe-d604256c3130

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Don't Conflate Entity, Handler and Projection → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Recommendation from the fourth anti-pattern.

relation (empty) → from_talk

source_node_id (empty) → 262ec9f9-ecce-45e4-a89e-f911cc32ef8a

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Scrutinize Community Thought Leaders → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Closing meta-advice section of the talk.

relation (empty) → from_talk

source_node_id (empty) → 9422601e-5bef-4592-9d34-f0027fc72672

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create A Week Of Up-Front Design Is Not Waterfall → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Closing 'measure twice, cut once' message.

relation (empty) → from_talk

source_node_id (empty) → ac2a1281-c415-4af1-b676-f479b63c6570

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Tooling Never Forced Your Monolith → from_talk → Event Sourcing Anti Patterns and Failures

context (empty) → Closing warning against blaming Rails or expecting Elixir to fix it.

relation (empty) → from_talk

source_node_id (empty) → c1573c68-a934-4eb9-b4ad-03a7f3f88523

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Keep Entities Free Of Messaging → about → Entity Coupled To Messaging

context (empty) → Directly addresses the first anti-pattern.

relation (empty) → about

source_node_id (empty) → 2feaa423-a235-428f-9c49-522c9aa8e25d

target_node_id (empty) → 464fbf52-5421-4819-b59c-959db0f9d819

create Events Record What Occurred, Nothing Else → about → View-Biased Event Schemas

context (empty) → Directly addresses the second anti-pattern.

relation (empty) → about

source_node_id (empty) → 68b76301-2620-41f1-9986-d1a4f5ca3553

target_node_id (empty) → 1879d94d-1505-48d7-88f5-b6d45eca370a

create Handlers Must Control Their Dependencies → about → Opaque Dependencies

context (empty) → Directly addresses the third anti-pattern.

relation (empty) → about

source_node_id (empty) → 4db2dafc-effc-4b7f-a2fe-d604256c3130

target_node_id (empty) → f7438446-2e23-45b0-a0df-81a1a77b29b8

create Don't Conflate Entity, Handler and Projection → about → Aggregate Root Anti-Pattern

context (empty) → Directly addresses the fourth anti-pattern.

relation (empty) → about

source_node_id (empty) → 262ec9f9-ecce-45e4-a89e-f911cc32ef8a

target_node_id (empty) → fd357908-6682-403f-9137-5349f516c23d

create What is an entity? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → ea4f4111-4363-46b5-86c5-7ca0092364b6

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Is the sufficient-funds check a feature envy smell? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → 415b1eca-d359-45ca-aaed-7200ec65bceb

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create What is the biggest challenge with this approach? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → 3b6e9374-558e-4321-ab14-4b575b7badf6

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create How is the event-write kept consistent with external operations? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → ec49a735-cc6b-48c8-b95c-344ec8dca4e1

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create How do you order events across distributed systems? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → 5fa0d9a9-0f0f-48c1-ae7f-716ed9a83d3a

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Do Rails adopters write handlers instead of controller actions? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → 775d9b1d-f988-4f02-842f-4ed0d6b58a93

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create How do you deal with event versioning? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → 061e7a74-be24-4db5-a2bb-81c2adb68f7e

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Centralised vs per-service event store? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → c54ca509-5844-48b4-8d53-4652722592bc

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create Do events store current state, and how does replay perform? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → 08d12182-f3bf-4a63-a0ee-29ac52b4c5b0

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create How do you deal with GDPR in an immutable event store? → asked_at → Event Sourcing Anti Patterns and Failures

context (empty) → Q&A after the talk.

relation (empty) → asked_at

source_node_id (empty) → ca8e147a-3331-498f-953e-1fad3fdf9bd4

target_node_id (empty) → 1a847342-76f9-432b-a5f5-82154448650d

create How do you order events across distributed systems? → about → Vector Clock

context (empty) → Ladd names vector clocks as the technical answer.

relation (empty) → about

source_node_id (empty) → 5fa0d9a9-0f0f-48c1-ae7f-716ed9a83d3a

target_node_id (empty) → d2d2adf5-34ca-4adc-9c3d-a54b6cb4851d

create How do you deal with event versioning? → about → Event Sourcing

context (empty) → Versioning strategies specific to event-sourced systems.

relation (empty) → about

source_node_id (empty) → 061e7a74-be24-4db5-a2bb-81c2adb68f7e

target_node_id (empty) → 687c9da2-de87-4fb2-a758-c7498f394fd5

create Do events store current state, and how does replay perform? → about → Entity Caching and Snapshotting

context (empty) → Answer describes version-keyed entity cache and periodic snapshots shipped by entity_store.

relation (empty) → about

source_node_id (empty) → 08d12182-f3bf-4a63-a0ee-29ac52b4c5b0

target_node_id (empty) → 4301ef2d-36cc-4513-b1be-2eaae118ce74

create Do events store current state, and how does replay perform? → about → Entity Store

context (empty) → Answer cites Eventide's entity_store library as providing the cache and snapshotting.

relation (empty) → about

source_node_id (empty) → 08d12182-f3bf-4a63-a0ee-29ac52b4c5b0

target_node_id (empty) → 111a5c90-99c8-44b7-8e32-b25d2b578053

create Centralised vs per-service event store? → about → Event Store

context (empty) → Answer contrasts event-store isolation properties with per-service relational DBs.

relation (empty) → about

source_node_id (empty) → c54ca509-5844-48b4-8d53-4652722592bc

target_node_id (empty) → 41e612ae-2c1f-4a3c-8690-d47ac47e0174

create Do Rails adopters write handlers instead of controller actions? → about → Command Message

context (empty) → Answer recommends having controllers write command messages to streams for portability.

relation (empty) → about

source_node_id (empty) → 775d9b1d-f988-4f02-842f-4ed0d6b58a93

target_node_id (empty) → 02772774-712b-4af2-9ec4-e4eafa94cb07

create Is the sufficient-funds check a feature envy smell? → about → Command Handler

context (empty) → Answer argues the decision belongs in the handler, not the entity.

relation (empty) → about

source_node_id (empty) → 415b1eca-d359-45ca-aaed-7200ec65bceb

target_node_id (empty) → e72326d6-a168-47a5-a1f7-dea8b50d49e3

create What is an entity? → related_to → Entity Projection

context (empty) → Asked to disambiguate 'entity' as used throughout the talk.

relation (empty) → related_to

source_node_id (empty) → ea4f4111-4363-46b5-86c5-7ca0092364b6

target_node_id (empty) → 28ae0d67-fcf9-4a6a-adb3-fb01e56cc520

Read set

97 nodes

36 edges

talk Toolbelt of a Seasoned Bug Hunter presented_at event wroclove.rb 2018

talk Applying CQRS & Event Sourcing on Rails applications presented_at event wroclove.rb 2018

person Adam Piotrowski attended event wroclove.rb 2018

person Arturo Herrero attended event wroclove.rb 2018

person Łukasz Szydło attended event wroclove.rb 2018

talk Event Sourcing Anti Patterns and Failures presented_at event wroclove.rb 2018

person Amelia Walter-Dzikowska attended event wroclove.rb 2018

talk Understanding coupling presented_at event wroclove.rb 2018

person Vladimir Dementyev attended event wroclove.rb 2018

talk Cables! Cables! Cables! presented_at event wroclove.rb 2018

person Damir Zekić attended event wroclove.rb 2018

talk Enterprise Rails Panel presented_at event wroclove.rb 2018

person Maciek attended event wroclove.rb 2018

talk MVCC for Ruby developers presented_at event wroclove.rb 2018

talk Counterintuitive Rails pt. 2 presented_at event wroclove.rb 2018

talk To Refine or Not to Refine presented_at event wroclove.rb 2018

talk Beyond the current state Time travel to the rescue! presented_at event wroclove.rb 2018

talk The pillars of Domain Driven Design presented_at event wroclove.rb 2018

person Ivan Nemytchenko attended event wroclove.rb 2018

person Nathan Ladd authored talk Event Sourcing Anti Patterns and Failures

talk Better WebPerformance with Rails presented_at event wroclove.rb 2018

talk JavaScript and Frontend Panel presented_at event wroclove.rb 2018

talk FaaS for Ruby Lightning Talk presented_at event wroclove.rb 2018

talk Removing Code with Breadth-First Search presented_at event wroclove.rb 2018

talk Ruby on a $4 Computer presented_at event wroclove.rb 2018

talk Developer, Programmer, and AI presented_at event wroclove.rb 2018

talk How wroclove.rb impacts developers and companies presented_at event wroclove.rb 2018

person Armin Pašalić attended event wroclove.rb 2018

person Sergey Ivanov attended event wroclove.rb 2018

person Marco Heimeshoff attended event wroclove.rb 2018

talk Sonic Pi Music Performance related_to event wroclove.rb 2018

person Nick Sutterer attended event wroclove.rb 2018

talk SUPER AIN'T SUPER From OOP To FP and Beyond! presented_at event wroclove.rb 2018

talk Methods Gem for Ruby Method References presented_at event wroclove.rb 2018

talk Counterintuitive Rails pt. 1 presented_at event wroclove.rb 2018

person Stefan Wintermeyer attended event wroclove.rb 2018