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PostgreSQL Glossary

Copy-on-Write (COW)

A resource management technique where data is shared until one process needs to modify it, then a copy is created. Example: Vela's copy-on-write cloning a…

Definition

A resource management technique where data is shared until one process needs to modify it, then a copy is created.

What Copy-on-Write (COW) Means in PostgreSQL

A resource management technique where data is shared until one process needs to modify it, then a copy is created.

Copy-on-Write (COW) appears frequently in production operations, architecture decisions, and troubleshooting workflows. Understanding this term helps teams reason about reliability, performance, and safe change management.

Why Copy-on-Write (COW) Matters

Teams that understand Copy-on-Write (COW) can make better decisions on database design, incident response, and release safety.

In modern PostgreSQL environments, this concept often connects directly to backup strategy, performance tuning, and operational confidence.

  • Improves decision quality for production operations
  • Reduces avoidable troubleshooting time
  • Strengthens reliability and recovery planning

Practical Example

Vela's copy-on-write cloning allows instant database copies that only use additional storage when data diverges.

Where To Learn More

You can explore deeper implementation patterns in the Vela articles library, review platform workflows in How Vela Works, and compare approaches in our PostgreSQL comparisons.

Related Glossary Topics

Connection Pooling Checkpoint Clone (Database Clone) ACID Atomicity Archiving (WAL Archiving) archive_command archive_mode

Frequently Asked Questions

What is Copy-on-Write (COW) in PostgreSQL?
A resource management technique where data is shared until one process needs to modify it, then a copy is created.
Why is Copy-on-Write (COW) important?
Copy-on-Write (COW) matters because it directly affects how teams build, operate, and recover PostgreSQL systems in production.
Can you give a practical Copy-on-Write (COW) example?
Vela's copy-on-write cloning allows instant database copies that only use additional storage when data diverges.
How does Copy-on-Write (COW) relate to backup, recovery, or performance?
In most production deployments, Copy-on-Write (COW) influences one or more of these areas: data safety, restore behavior, and performance under load.
What should teams check first when implementing Copy-on-Write (COW)?
Start with clear operational goals, test in a non-production environment, and validate behavior with repeatable runbooks before relying on it in production.