What Is JOIN?
A JOIN combines rows from two or more tables based on a common column. PostgreSQL supports INNER, LEFT, RIGHT, FULL, and CROSS JOINs. It's essential for querying normalized data.
Why It Matters for PostgreSQL Performance
In PostgreSQL performance work, JOIN affects throughput, latency, or operational reliability depending on workload and configuration.
Practical Benchmarking Context
When benchmarking with pgbench, track how JOIN 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: SELECT * FROM orders JOIN users ON orders.user_id = users.id;