What Is Domain?
A domain is a custom data type with constraints like CHECK. It allows for reusability and consistent data validation.
Why It Matters for PostgreSQL Performance
In PostgreSQL performance work, Domain affects throughput, latency, or operational reliability depending on workload and configuration.
Practical Benchmarking Context
When benchmarking with pgbench, track how Domain changes behavior across scale factor, client concurrency, and storage conditions.
Use this term together with workload shape, concurrency level, and scale factor when interpreting pgbench outputs. Isolated values can be misleading without full run context.
Example
Example: CREATE DOMAIN email AS TEXT CHECK (...);