What Is FILLFACTOR?
FILLFACTOR determines how much of a data page PostgreSQL fills initially. A lower value leaves more space for updates, reducing page splits and maintaining performance. It's useful for update-heavy tables.
Why It Matters for PostgreSQL Performance
In PostgreSQL performance work, FILLFACTOR affects throughput, latency, or operational reliability depending on workload and configuration.
Practical Benchmarking Context
When benchmarking with pgbench, track how FILLFACTOR 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
Set: CREATE TABLE t (id int) WITH (fillfactor = 70);