# Isolation

> A rule or precondition that concurrent transactions do not see each other's uncommitted changes, to the degree the isolation level declares.

Record: `architecture:isolation`
Kind: constraint
Layer: [Atomic Boundary](https://banes-lab.com/records/layer/atomic-boundary.md)
Severity: contextual
Scope: database, transaction, concurrency
Canonical: https://banes-lab.com/ontology#architecture-isolation

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Consistency](https://banes-lab.com/records/architecture/consistency.md) and before [Concurrency Control](https://banes-lab.com/records/architecture/concurrency-control.md).

## Repair

- Refactored by: Add Locking, Set Isolation Level
- Detected by: concurrency tests, isolation anomalies
- Violated by: race-condition state corruption
- Measured by: anomaly rate, lock contention
- Enforced by: DB isolation, concurrency tests

## Requires

- [Concurrency Control](https://banes-lab.com/records/architecture/concurrency-control.md)

## Reinforces

- [Correctness](https://banes-lab.com/records/architecture/correctness.md)

## Enables

- [Safe Concurrent Operations](https://banes-lab.com/records/lexicon/safe-concurrent-operations.md)

## Conflicts with

- [Dirty Reads/Writes](https://banes-lab.com/records/lexicon/dirty-reads-writes.md)

## In tension with

- [Throughput](https://banes-lab.com/records/architecture/throughput.md)

## Tensions

- [Isolation / Throughput](https://banes-lab.com/records/tension/isolation-throughput.md)

## Severity

- [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md)

## Category

- [Transactions / State / Concurrency](https://banes-lab.com/records/architecture-category/transactions-state-concurrency.md)

## Reinforced by

- [Partitioning](https://banes-lab.com/records/architecture/partitioning.md)
- [Pessimistic Locking](https://banes-lab.com/records/architecture/pessimistic-locking.md)

## Required by

- [ACID](https://banes-lab.com/records/architecture/acid.md)

## Linked from

- [Correctness / Determinism / Verification](https://banes-lab.com/ontology/principles/architecture-category-correctness-determinism-verification.md)
- [Scalability / Performance / Optimization](https://banes-lab.com/ontology/principles/architecture-category-scalability-performance-optimization.md)
- [Transactions / State / Concurrency](https://banes-lab.com/ontology/principles/architecture-category-transactions-state-concurrency.md)
- [Transactions / State / Concurrency](https://banes-lab.com/ontology/lexicon/lexicon-category-transactions-state-concurrency.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)