Fraction of the interval over which to spread checkpoint writes.
At a glance
| Property | Value |
|---|---|
| Parameter | checkpoint_completion_target |
| Category | Checkpoints |
| Default | 0.9 |
| Value type | boolean / enum / numeric |
| Change scope | Reload (no restart) |
What it does
Spreads checkpoint write I/O over this fraction of the checkpoint interval, smoothing the I/O spike. Default raised to 0.9 in PG14.
How to apply a change
Takes effect on configuration reload (sighup context). Run SELECT pg_reload_conf(); or send SIGHUP — no restart needed.
Inspect the current value and source with SHOW checkpoint_completion_target; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'checkpoint_completion_target';.
Tuning guidance
Leave at 0.9. Together with a larger checkpoint_timeout this avoids sharp I/O peaks that stall queries.