seq_page_cost
No restart — settable per sessioncost factor (the 1.0 baseline)
The planner's baseline cost for reading one page sequentially.
What it does
seq_page_cost is the reference unit (default 1.0) every other cost is measured against — most importantly random_page_cost, which is expressed as a multiple of it. Lowering or raising it rescales how page reads compare to CPU costs like cpu_tuple_cost.
How to tune it
Usually leave it at 1.0 and adjust random_page_cost instead — the ratio between them is what matters for index-vs-seq-scan. Advanced setups occasionally lower both page costs together when almost everything is cached, to make CPU costs relatively more significant.