What does nprobe do when the index is FLAT?

[JeroenVanOort]

I think I understand the significance of nprobe when using any index but FLAT. But does it's value make any difference when the index is FLAT?

[sahuang]

nprobe will never be checked in FLAT index. In fact we do not care about the parameter when using FLAT.

[JeroenVanOort]

Thanks!