[HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes areenabled

Hi,

I was reading the blog https://blog.2ndquadrant.com/on-the-impact-of-full-page-writes .

My queries:

How randomness of UUID will likely to create new leaf page in btree index?
In my understanding as the size of UUID is 128 bits i.e. twice of BIGSERIAL , more number of pages will be required to store the same number of rows and hence there can be increase in WAL size due to FPW .
When compared the index size in local setup UUID index is ~2x greater in size.

Thanks,

Sanyam Jain