N Plus One Query

Kind: anti-pattern

Layer: Enforcement Core

Aliases: N+1 Query

Record: architecture:n-plus-one-query

Severity: discouraged

Scope: architecture_evolution

Formed by: Fetch a collection, then issue one query or remote call per item rather than fetching required related data intentionally.

Canonical: Ontology

A defect in which a collection is fetched and then one further query is issued per item.

Listed in Architecture principles, after Chatty Interface and before Cache Poisoning by Design.

Refactored by

• Batch Fetch
• Query Projection

Severity

• discouraged

Category

• Anti-patterns

Force

• Architecture evolution

Negated by

• Algorithmic Efficiency

Linked from

• Anti-patterns
• Scalability / Performance / Optimization
• Event Messaging Async
• Scalability / Performance / Optimization
• Severity levels
• The forces