What Is Key Constraint?
A key constraint ensures uniqueness and integrity in a PostgreSQL table. It can be a primary key or a unique constraint. These are enforced automatically during inserts and updates.
Why It Matters for PostgreSQL Performance
In PostgreSQL performance work, Key Constraint affects throughput, latency, or operational reliability depending on workload and configuration.
Practical Benchmarking Context
When benchmarking with pgbench, track how Key Constraint 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
Usage: PRIMARY KEY (id) or UNIQUE (email)