BGP AIGP and BGP churn

I have read BGP churn before, I find the meaning and then forget about it until next time.

BGP churn = the rate of routing updates that BGP routers must process.

And I can’t really find a straight definition.

As well, I didnt know the actual meaning of churn was. So it s a machine to produce butter and the amount of customer stopping using a product.

I read at work something about AIGP from a different department. I searched and found that is a new BGP optional non-transitive path attribute and the BGP decision process is updated for that. And this is from 2015!!! So I am 6 years behind…. And there is a RFC7311

Note: BGP routers that do not support the optional non-transitive attributes (e.g. AIGP) must delete such attributes and must not pass them to other BGP peers.

So it seems a good feature if you run a big AS and want BGP to take into account the IGP cost.