What Is NOT NULL?
The NOT NULL constraint ensures that a column cannot have NULL values. It’s a basic yet critical rule to enforce data presence. PostgreSQL uses it to guarantee data integrity at the schema level.
Why It Matters for PostgreSQL Performance
In PostgreSQL performance work, NOT NULL affects throughput, latency, or operational reliability depending on workload and configuration.
Practical Benchmarking Context
When benchmarking with pgbench, track how NOT NULL 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 TABLE users (email TEXT NOT NULL);