What Is Foreign Key?
A foreign key enforces a relationship between two tables to maintain referential integrity. PostgreSQL ensures the referenced row exists before allowing inserts or updates. It's a cornerstone of relational database design.
Why It Matters for PostgreSQL Performance
In PostgreSQL performance work, Foreign Key affects throughput, latency, or operational reliability depending on workload and configuration.
Practical Benchmarking Context
When benchmarking with pgbench, track how Foreign Key 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
Syntax: FOREIGN KEY (user_id) REFERENCES users(id)