Also called: apply delay setting
In plain English
recovery_min_apply_delay is the standby setting that creates a delayed standby. It tells the startup process to wait until a transaction’s commit timestamp plus this interval has passed before applying that commit’s WAL. The logic lives in recoveryApplyDelay() and keys off the timestamps carried in commit records.
Why it matters
It sets the size of your operator-error undo window. Bigger means more time to react to a mistake, but staler reads on that replica and more WAL to retain. Don’t combine it with synchronous_commit = remote_apply, which would stall every commit on the primary by the full delay.